diff --git a/src/server/game/AI/CoreAI/GuardAI.cpp b/src/server/game/AI/CoreAI/GuardAI.cpp
index abce4d1d39..f2ea7442f2 100644
--- a/src/server/game/AI/CoreAI/GuardAI.cpp
+++ b/src/server/game/AI/CoreAI/GuardAI.cpp
@@ -57,7 +57,7 @@ void GuardAI::EnterEvadeMode(EvadeReason /*why*/)
     {
         me->GetMotionMaster()->MoveIdle();
         me->CombatStop(true);
-        me->GetThreatManager().NotifyDisengaged();
+        EngagementOver();
         return;
     }
 
@@ -65,7 +65,7 @@ void GuardAI::EnterEvadeMode(EvadeReason /*why*/)
 
     me->RemoveAllAuras();
     me->CombatStop(true);
-    me->GetThreatManager().NotifyDisengaged();
+    EngagementOver();
 
     // Remove ChaseMovementGenerator from MotionMaster stack list, and add HomeMovementGenerator instead
     if (me->GetMotionMaster()->GetCurrentMovementGeneratorType() == CHASE_MOTION_TYPE)
diff --git a/src/server/game/AI/CoreAI/PassiveAI.h b/src/server/game/AI/CoreAI/PassiveAI.h
index bf593f83c2..4e80510e7f 100644
--- a/src/server/game/AI/CoreAI/PassiveAI.h
+++ b/src/server/game/AI/CoreAI/PassiveAI.h
@@ -39,6 +39,9 @@ class TC_GAME_API PossessedAI : public CreatureAI
 
         void MoveInLineOfSight(Unit*) override { }
         void AttackStart(Unit* target) override;
+        void JustEnteredCombat(Unit* who) override { EngagementStart(who); }
+        void JustExitedCombat() override { EngagementOver(); }
+        void JustStartedThreateningMe(Unit*) override { }
         void UpdateAI(uint32) override;
         void EnterEvadeMode(EvadeReason /*why*/) override { }
 
@@ -57,6 +60,8 @@ class TC_GAME_API NullCreatureAI : public CreatureAI
 
         void MoveInLineOfSight(Unit*) override { }
         void AttackStart(Unit*) override { }
+        void JustStartedThreateningMe(Unit*) override { }
+        void JustEnteredCombat(Unit*) override { }
         void UpdateAI(uint32) override { }
         void JustAppeared() override { }
         void EnterEvadeMode(EvadeReason /*why*/) override { }
diff --git a/src/server/game/AI/CoreAI/TotemAI.cpp b/src/server/game/AI/CoreAI/TotemAI.cpp
index 533e489d85..7e083b04e7 100644
--- a/src/server/game/AI/CoreAI/TotemAI.cpp
+++ b/src/server/game/AI/CoreAI/TotemAI.cpp
@@ -32,16 +32,9 @@ int32 TotemAI::Permissible(Creature const* creature)
     return PERMIT_BASE_NO;
 }
 
-TotemAI::TotemAI(Creature* c) : CreatureAI(c), i_victimGuid()
+TotemAI::TotemAI(Creature* creature) : NullCreatureAI(creature), _victimGUID()
 {
-    ASSERT(c->IsTotem());
-}
-
-void TotemAI::MoveInLineOfSight(Unit* /*who*/) { }
-
-void TotemAI::EnterEvadeMode(EvadeReason /*why*/)
-{
-    me->CombatStop(true);
+    ASSERT(creature->IsTotem(), "TotemAI: AI assigned to a non-totem creature (%s)!", creature->GetGUID().ToString().c_str());
 }
 
 void TotemAI::UpdateAI(uint32 /*diff*/)
@@ -63,7 +56,7 @@ void TotemAI::UpdateAI(uint32 /*diff*/)
     // SPELLMOD_RANGE not applied in this place just because not existence range mods for attacking totems
 
     // pointer to appropriate target if found any
-    Unit* victim = i_victimGuid ? ObjectAccessor::GetUnit(*me, i_victimGuid) : nullptr;
+    Unit* victim = _victimGUID ? ObjectAccessor::GetUnit(*me, _victimGUID) : nullptr;
 
     // Search victim if no, not attackable, or out of range, or friendly (possible in case duel end)
     if (!victim ||
@@ -80,14 +73,14 @@ void TotemAI::UpdateAI(uint32 /*diff*/)
     if (victim)
     {
         // remember
-        i_victimGuid = victim->GetGUID();
+        _victimGUID = victim->GetGUID();
 
         // attack
         me->SetInFront(victim);                         // client change orientation by self
         me->CastSpell(victim, me->ToTotem()->GetSpell(), false);
     }
     else
-        i_victimGuid.Clear();
+        _victimGUID.Clear();
 }
 
 void TotemAI::AttackStart(Unit* /*victim*/)
diff --git a/src/server/game/AI/CoreAI/TotemAI.h b/src/server/game/AI/CoreAI/TotemAI.h
index d28ede8a25..95362a8079 100644
--- a/src/server/game/AI/CoreAI/TotemAI.h
+++ b/src/server/game/AI/CoreAI/TotemAI.h
@@ -19,26 +19,24 @@
 #define TRINITY_TOTEMAI_H
 
 #include "CreatureAI.h"
+#include "PassiveAI.h"
 #include "Timer.h"
 
 class Creature;
 class Totem;
 
-class TC_GAME_API TotemAI : public CreatureAI
+class TC_GAME_API TotemAI : public NullCreatureAI
 {
     public:
 
         explicit TotemAI(Creature* c);
 
-        void MoveInLineOfSight(Unit* who) override;
         void AttackStart(Unit* victim) override;
-        void JustAppeared() override { }
-        void EnterEvadeMode(EvadeReason /*why*/) override;
 
         void UpdateAI(uint32 diff) override;
         static int32 Permissible(Creature const* creature);
 
     private:
-        ObjectGuid i_victimGuid;
+        ObjectGuid _victimGUID;
 };
 #endif
diff --git a/src/server/game/AI/CoreAI/UnitAI.cpp b/src/server/game/AI/CoreAI/UnitAI.cpp
index c6ce618776..317734c64b 100644
--- a/src/server/game/AI/CoreAI/UnitAI.cpp
+++ b/src/server/game/AI/CoreAI/UnitAI.cpp
@@ -254,7 +254,7 @@ void UnitAI::SortByDistance(std::list<Unit*> list, bool ascending)
 }
 
 DefaultTargetSelector::DefaultTargetSelector(Unit const* unit, float dist, bool playerOnly, bool withTank, int32 aura)
-    : me(unit), m_dist(dist), m_playerOnly(playerOnly), except(!withTank ? unit->GetThreatManager().GetCurrentVictim() : nullptr), m_aura(aura)
+    : me(unit), m_dist(dist), m_playerOnly(playerOnly), except(!withTank ? unit->GetThreatManager().GetLastVictim() : nullptr), m_aura(aura)
 {
 }
 
diff --git a/src/server/game/AI/CreatureAI.cpp b/src/server/game/AI/CreatureAI.cpp
index 98a018e9ed..cc941f3fc7 100644
--- a/src/server/game/AI/CreatureAI.cpp
+++ b/src/server/game/AI/CreatureAI.cpp
@@ -46,7 +46,7 @@ void CreatureAI::OnCharmed(bool apply)
 AISpellInfoType* UnitAI::AISpellInfo;
 AISpellInfoType* GetAISpellInfo(uint32 i) { return &UnitAI::AISpellInfo[i]; }
 
-CreatureAI::CreatureAI(Creature* creature) : UnitAI(creature), me(creature), _boundary(nullptr), _negateBoundary(false), m_MoveInLineOfSight_locked(false)
+CreatureAI::CreatureAI(Creature* creature) : UnitAI(creature), me(creature), _boundary(nullptr), _negateBoundary(false), _isEngaged(false), _moveInLOSLocked(false)
 {
 }
 
@@ -96,11 +96,11 @@ void CreatureAI::DoZoneInCombat(Creature* creature /*= nullptr*/)
 // MoveInLineOfSight can be called inside another MoveInLineOfSight and cause stack overflow
 void CreatureAI::MoveInLineOfSight_Safe(Unit* who)
 {
-    if (m_MoveInLineOfSight_locked == true)
+    if (_moveInLOSLocked == true)
         return;
-    m_MoveInLineOfSight_locked = true;
+    _moveInLOSLocked = true;
     MoveInLineOfSight(who);
-    m_MoveInLineOfSight_locked = false;
+    _moveInLOSLocked = false;
 }
 
 void CreatureAI::MoveInLineOfSight(Unit* who)
@@ -183,7 +183,7 @@ static bool ShouldFollowOnSpawn(SummonPropertiesEntry const* properties)
 }
 void CreatureAI::JustAppeared()
 {
-    if (!me->IsInCombat())
+    if (!IsEngaged())
     {
         if (TempSummon* summon = me->ToTempSummon())
         {
@@ -200,6 +200,12 @@ void CreatureAI::JustAppeared()
     }
 }
 
+void CreatureAI::JustEnteredCombat(Unit* who)
+{
+    if (!IsEngaged() && !me->CanHaveThreatList())
+        EngagementStart(who);
+}
+
 void CreatureAI::EnterEvadeMode(EvadeReason why)
 {
     if (!_EnterEvadeMode(why))
@@ -225,7 +231,7 @@ void CreatureAI::EnterEvadeMode(EvadeReason why)
 
 bool CreatureAI::UpdateVictim()
 {
-    if (!me->IsEngaged())
+    if (!IsEngaged())
         return false;
 
     if (!me->HasReactState(REACT_PASSIVE))
@@ -247,15 +253,44 @@ bool CreatureAI::UpdateVictim()
     return true;
 }
 
+void CreatureAI::EngagementStart(Unit* who)
+{
+    if (_isEngaged)
+    {
+        TC_LOG_ERROR("scripts.ai", "CreatureAI::EngagementStart called even though creature is already engaged.");
+        return;
+    }
+    _isEngaged = true;
+
+    me->AtEngage(who);
+}
+
+void CreatureAI::EngagementOver()
+{
+    if (!_isEngaged)
+    {
+        TC_LOG_ERROR("scripts.ai", "CreatureAI::EngagementOver called even though creature is not currently engaged.");
+        return;
+    }
+    _isEngaged = false;
+
+    me->AtDisengage();
+}
+
 bool CreatureAI::_EnterEvadeMode(EvadeReason /*why*/)
 {
-    if (!me->IsAlive())
+    if (me->IsInEvadeMode())
         return false;
 
+    if (!me->IsAlive())
+    {
+        EngagementOver();
+        return false;
+    }
+
     me->RemoveAurasOnEvade();
 
     me->CombatStop(true);
-    me->GetThreatManager().NotifyDisengaged();
     me->LoadCreaturesAddon();
     me->SetLootRecipient(nullptr);
     me->ResetPlayerDamageReq();
@@ -265,7 +300,9 @@ bool CreatureAI::_EnterEvadeMode(EvadeReason /*why*/)
     me->GetSpellHistory()->ResetAllCooldowns();
     me->SetTarget(ObjectGuid::Empty);
 
-    return !me->IsInEvadeMode();
+    EngagementOver();
+
+    return true;
 }
 
 const uint32 BOUNDARY_VISUALIZE_CREATURE = 15425;
diff --git a/src/server/game/AI/CreatureAI.h b/src/server/game/AI/CreatureAI.h
index 99a76425f2..fdb2869a59 100644
--- a/src/server/game/AI/CreatureAI.h
+++ b/src/server/game/AI/CreatureAI.h
@@ -96,6 +96,8 @@ class TC_GAME_API CreatureAI : public UnitAI
 
         ~CreatureAI();
 
+        bool IsEngaged() const { return _isEngaged; }
+
         void Talk(uint8 id, WorldObject const* whisperTarget = nullptr);
 
         /// == Reactions At =================================
@@ -109,11 +111,17 @@ class TC_GAME_API CreatureAI : public UnitAI
         // Called for reaction at stopping attack at no attackers or targets
         virtual void EnterEvadeMode(EvadeReason why = EVADE_REASON_OTHER);
 
+        // Called for reaction whenever we start being in combat (overridden from base UnitAI)
+        void JustEnteredCombat(Unit* /*who*/) override;
+
+        // Called for reaction whenever a new non-offline unit is added to the threat list
+        virtual void JustStartedThreateningMe(Unit* who) { if (!IsEngaged()) EngagementStart(who); }
+
         // Called for reaction when initially engaged
         virtual void JustEngagedWith(Unit* /*who*/) { }
 
         // Called when the creature is killed
-        virtual void JustDied(Unit* /*killer*/) { }
+        virtual void JustDied(Unit* /*killer*/) { if (IsEngaged()) EngagementOver(); }
 
         // Called when the creature kills a unit
         virtual void KilledUnit(Unit* /*victim*/) { }
@@ -227,6 +235,8 @@ class TC_GAME_API CreatureAI : public UnitAI
 
         // intended for encounter design/debugging. do not use for other purposes. expensive.
         int32 VisualizeBoundary(uint32 duration, Unit* owner = nullptr, bool fill = false) const;
+
+        // boundary system methods
         virtual bool CheckInRoom();
         CreatureBoundary const* GetBoundary() const { return _boundary; }
         void SetBoundary(CreatureBoundary const* boundary, bool negativeBoundaries = false);
@@ -234,6 +244,8 @@ class TC_GAME_API CreatureAI : public UnitAI
         static bool IsInBounds(CreatureBoundary const& boundary, Position const* who);
 
     protected:
+        void EngagementStart(Unit* who);
+        void EngagementOver();
         virtual void MoveInLineOfSight(Unit* /*who*/);
 
         bool _EnterEvadeMode(EvadeReason why = EVADE_REASON_OTHER);
@@ -242,7 +254,8 @@ class TC_GAME_API CreatureAI : public UnitAI
         bool _negateBoundary;
 
     private:
-        bool m_MoveInLineOfSight_locked;
+        bool _isEngaged;
+        bool _moveInLOSLocked;
         void _OnOwnerCombatInteraction(Unit* target);
 };
 
diff --git a/src/server/game/AI/ScriptedAI/ScriptedEscortAI.cpp b/src/server/game/AI/ScriptedAI/ScriptedEscortAI.cpp
index 26b7d042cb..f1f59505e7 100644
--- a/src/server/game/AI/ScriptedAI/ScriptedEscortAI.cpp
+++ b/src/server/game/AI/ScriptedAI/ScriptedEscortAI.cpp
@@ -132,9 +132,10 @@ void EscortAI::EnterEvadeMode(EvadeReason /*why*/)
 {
     me->RemoveAllAuras();
     me->CombatStop(true);
-    me->GetThreatManager().NotifyDisengaged();
     me->SetLootRecipient(nullptr);
 
+    EngagementOver();
+
     if (HasEscortState(STATE_ESCORT_ESCORTING))
     {
         AddEscortState(STATE_ESCORT_RETURNING);
diff --git a/src/server/game/Combat/CombatManager.cpp b/src/server/game/Combat/CombatManager.cpp
index 92f3edbab2..efd0766e22 100644
--- a/src/server/game/Combat/CombatManager.cpp
+++ b/src/server/game/Combat/CombatManager.cpp
@@ -292,13 +292,8 @@ void CombatManager::EndAllPvPCombat()
 
 /*static*/ void CombatManager::NotifyAICombat(Unit* me, Unit* other)
 {
-    if (!me->IsAIEnabled)
-        return;
-    me->GetAI()->JustEnteredCombat(other);
-
-    if (Creature* cMe = me->ToCreature())
-        if (!cMe->CanHaveThreatList())
-            cMe->AI()->JustEngagedWith(other);
+    if (UnitAI* ai = me->GetAI())
+        ai->JustEnteredCombat(other);
 }
 
 void CombatManager::PutReference(ObjectGuid const& guid, CombatReference* ref)
@@ -335,14 +330,14 @@ bool CombatManager::UpdateOwnerCombatState() const
     {
         _owner->SetFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_IN_COMBAT);
         _owner->AtEnterCombat();
-        if (!_owner->CanHaveThreatList() && !_owner->IsEngaged())
+        if (_owner->GetTypeId() == TYPEID_UNIT)
             _owner->AtEngage(GetAnyTarget());
     }
     else
     {
         _owner->RemoveFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_IN_COMBAT);
         _owner->AtExitCombat();
-        if (_owner->IsEngaged() && !(_owner->ToCreature() && _owner->ToCreature()->IsAIEnabled))
+        if (_owner->GetTypeId() == TYPEID_UNIT)
             _owner->AtDisengage();
     }
 
diff --git a/src/server/game/Combat/ThreatManager.cpp b/src/server/game/Combat/ThreatManager.cpp
index 90c721f0c2..112adba0f5 100644
--- a/src/server/game/Combat/ThreatManager.cpp
+++ b/src/server/game/Combat/ThreatManager.cpp
@@ -15,12 +15,13 @@
  * with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "ThreatManager.h"
 #include "Creature.h"
 #include "CreatureAI.h"
 #include "CreatureGroups.h"
 #include "MotionMaster.h"
 #include "Player.h"
-#include "ThreatManager.h"
+#include "TemporarySummon.h"
 #include "Unit.h"
 #include "UnitAI.h"
 #include "UnitDefines.h"
@@ -73,6 +74,7 @@ void ThreatReference::UpdateOffline()
     {
         _online = ShouldBeSuppressed() ? ONLINE_STATE_SUPPRESSED : ONLINE_STATE_ONLINE;
         HeapNotifyIncreased();
+        _mgr.RegisterForAIUpdate(this);
     }
 }
 
@@ -159,9 +161,11 @@ void ThreatReference::UnregisterAndFree()
     if (cWho->IsPet() || cWho->IsTotem() || cWho->IsTrigger())
         return false;
 
-    // summons cannot have a threat list, unless they are controlled by a creature
-    if (cWho->HasUnitTypeMask(UNIT_MASK_MINION | UNIT_MASK_GUARDIAN) && !cWho->GetOwnerGUID().IsCreature())
-        return false;
+    // summons cannot have a threat list if they were summoned by a player
+    if (cWho->HasUnitTypeMask(UNIT_MASK_MINION | UNIT_MASK_GUARDIAN))
+        if (TempSummon const* tWho = cWho->ToTempSummon())
+            if (tWho->GetSummonerGUID().IsPlayer())
+                return false;
 
     return true;
 }
@@ -201,10 +205,11 @@ Unit* ThreatManager::GetCurrentVictim()
 {
     if (!_currentVictimRef || _currentVictimRef->ShouldBeOffline())
         UpdateVictim();
-    return const_cast<ThreatManager const*>(this)->GetCurrentVictim();
+    ASSERT(!_currentVictimRef || _currentVictimRef->IsAvailable());
+    return _currentVictimRef ? _currentVictimRef->GetVictim() : nullptr;
 }
 
-Unit* ThreatManager::GetCurrentVictim() const
+Unit* ThreatManager::GetLastVictim() const
 {
     if (_currentVictimRef && !_currentVictimRef->ShouldBeOffline())
         return _currentVictimRef->GetVictim();
@@ -246,7 +251,7 @@ float ThreatManager::GetThreat(Unit const* who, bool includeOffline) const
     return (includeOffline || it->second->IsAvailable()) ? it->second->GetThreat() : 0.0f;
 }
 
-std::vector<ThreatReference*> ThreatManager::GetModifiableThreatList() const
+std::vector<ThreatReference*> ThreatManager::GetModifiableThreatList()
 {
     std::vector<ThreatReference*> list;
     list.reserve(_myThreatListEntries.size());
@@ -386,16 +391,14 @@ void ThreatManager::AddThreat(Unit* target, float amount, SpellInfo const* spell
     PutThreatListRef(target->GetGUID(), ref);
     target->GetThreatManager().PutThreatenedByMeRef(_owner->GetGUID(), ref);
 
-    // afterwards, we evaluate whether this is an online reference (it might not be an acceptable target, but we need to add it to our threat list before we check!)
     ref->UpdateOffline();
-    if (ref->IsOnline()) // ...and if the ref is online it also gets the threat it should have
+    if (ref->IsOnline()) // we only add the threat if the ref is currently available
         ref->AddThreat(amount);
 
-    if (!_owner->IsEngaged())
-    {
-        _owner->AtEngage(target);
+    if (!_currentVictimRef)
         UpdateVictim();
-    }
+    else
+        ProcessAIUpdates();
 }
 
 void ThreatManager::ScaleThreat(Unit* target, float factor)
@@ -480,14 +483,6 @@ void ThreatManager::ClearAllThreat()
     }
 }
 
-void ThreatManager::NotifyDisengaged()
-{
-    // note: i don't really like having this here
-    // (maybe engage flag should be in creature ai? it's inherently an AI property...)
-    if (_owner->IsEngaged())
-        _owner->AtDisengage();
-}
-
 void ThreatManager::FixateTarget(Unit* target)
 {
     if (target)
@@ -522,6 +517,7 @@ void ThreatManager::UpdateVictim()
         _needClientUpdate = false;
     }
 
+    ProcessAIUpdates();
 }
 
 ThreatReference const* ThreatManager::ReselectVictim()
@@ -530,7 +526,7 @@ ThreatReference const* ThreatManager::ReselectVictim()
         return nullptr;
 
     for (auto const& pair : _myThreatListEntries)
-        pair.second->UpdateOffline();
+        pair.second->UpdateOffline(); // AI notifies are processed in ::UpdateVictim caller
 
     // fixated target is always preferred
     if (_fixateRef && _fixateRef->IsAvailable())
@@ -579,6 +575,16 @@ ThreatReference const* ThreatManager::ReselectVictim()
     return nullptr;
 }
 
+void ThreatManager::ProcessAIUpdates()
+{
+    CreatureAI* ai = ASSERT_NOTNULL(_owner->ToCreature())->AI();
+    std::vector<ThreatReference const*> v(std::move(_needsAIUpdate)); // _needClientUpdate is now empty in case this triggers a recursive call
+    if (!ai)
+        return;
+    for (ThreatReference const* ref : v)
+        ai->JustStartedThreateningMe(ref->GetVictim());
+}
+
 // returns true if a is LOWER on the threat list than b
 /*static*/ bool ThreatManager::CompareReferencesLT(ThreatReference const* a, ThreatReference const* b, float aWeight)
 {
diff --git a/src/server/game/Combat/ThreatManager.h b/src/server/game/Combat/ThreatManager.h
index 6e4f20c55a..8e722707f9 100644
--- a/src/server/game/Combat/ThreatManager.h
+++ b/src/server/game/Combat/ThreatManager.h
@@ -103,7 +103,7 @@ class TC_GAME_API ThreatManager
         bool CanHaveThreatList() const { return _ownerCanHaveThreatList; }
         // returns the current victim - this can be nullptr if owner's threat list is empty, or has only offline targets
         Unit* GetCurrentVictim();
-        Unit* GetCurrentVictim() const;
+        Unit* GetLastVictim() const;
         // returns an arbitrary non-offline victim from owner's threat list if one exists, nullptr otherwise
         Unit* GetAnyTarget() const;
 
@@ -121,10 +121,10 @@ class TC_GAME_API ThreatManager
         Trinity::IteratorPair<ThreatListIterator> GetUnsortedThreatList() const { return { _myThreatListEntries.begin(), _myThreatListEntries.end() }; }
         // slightly slower than GetUnsorted, but, well...sorted - only use it if you need the sorted property, of course
         // this iterator pair will invalidate on any modification (even indirect) of the threat list; spell casts and similar can all induce this!
-        // note: current tank is NOT guaranteed to be the first entry in this list - check GetCurrentVictim separately if you want that!
+        // note: current tank is NOT guaranteed to be the first entry in this list - check GetLastVictim separately if you want that!
         Trinity::IteratorPair<threat_list_heap::ordered_iterator> GetSortedThreatList() const { return { _sortedThreatList.ordered_begin(), _sortedThreatList.ordered_end() }; }
         // slowest of the three threat list getters (by far), but lets you modify the threat references - this is also sorted
-        std::vector<ThreatReference*> GetModifiableThreatList() const;
+        std::vector<ThreatReference*> GetModifiableThreatList();
 
         // does any unit have a threat list entry with victim == this.owner?
         bool IsThreateningAnyone(bool includeOffline = false) const;
@@ -154,9 +154,6 @@ class TC_GAME_API ThreatManager
         void ClearThreat(ThreatReference* ref);
         // Removes all targets from the threat list (will cause evade in UpdateVictim if called)
         void ClearAllThreat();
-        // THIS SHOULD ONLY BE CALLED FROM A CREATURE'S AI (typically in EnterEvadeMode)
-        // notify the unit that the AI has disengaged
-        void NotifyDisengaged();
 
         // Fixate on the passed target; this target will always be selected until the fixate is cleared
         // (if the target is not in the threat list, does nothing)
@@ -204,6 +201,12 @@ class TC_GAME_API ThreatManager
         threat_list_heap _sortedThreatList;
         std::unordered_map<ObjectGuid, ThreatReference*> _myThreatListEntries;
 
+        // AI notifies are delayed to ensure we are in a consistent state before we call out to arbitrary logic
+        // threat references might register themselves here when ::UpdateOffline() is called - MAKE SURE THIS IS PROCESSED JUST BEFORE YOU EXIT THREATMANAGER LOGIC
+        void ProcessAIUpdates();
+        void RegisterForAIUpdate(ThreatReference const* ref) { _needsAIUpdate.push_back(ref); }
+        std::vector<ThreatReference const*> _needsAIUpdate;
+
         // picks a new victim - called from ::Update periodically
         void UpdateVictim();
         ThreatReference const* ReselectVictim();
@@ -278,7 +281,7 @@ class TC_GAME_API ThreatReference
             _owner(reinterpret_cast<Creature*>(mgr->_owner)), _mgr(*mgr), _victim(victim),
             _baseAmount(0.0f), _tempModifier(0), _taunted(TAUNT_STATE_NONE)
         {
-            _online = ShouldBeSuppressed() ? ONLINE_STATE_SUPPRESSED : ONLINE_STATE_ONLINE;
+            _online = ONLINE_STATE_OFFLINE;
         }
 
         void UnregisterAndFree();
diff --git a/src/server/game/Entities/Creature/Creature.cpp b/src/server/game/Entities/Creature/Creature.cpp
index 05b59268de..652cb47033 100644
--- a/src/server/game/Entities/Creature/Creature.cpp
+++ b/src/server/game/Entities/Creature/Creature.cpp
@@ -3201,6 +3201,13 @@ bool Creature::CanGiveExperience() const
         && !(GetCreatureTemplate()->flags_extra & CREATURE_FLAG_EXTRA_NO_XP_AT_KILL);
 }
 
+bool Creature::IsEngaged() const
+{
+    if (CreatureAI const* ai = AI())
+        return ai->IsEngaged();
+    return false;
+}
+
 void Creature::AtEngage(Unit* target)
 {
     Unit::AtEngage(target);
diff --git a/src/server/game/Entities/Creature/Creature.h b/src/server/game/Entities/Creature/Creature.h
index cf5ea1dd16..b511229b25 100644
--- a/src/server/game/Entities/Creature/Creature.h
+++ b/src/server/game/Entities/Creature/Creature.h
@@ -358,6 +358,7 @@ class TC_GAME_API Creature : public Unit, public GridObject<Creature>, public Ma
 
         void MakeInterruptable(bool apply);
 
+        bool IsEngaged() const override;
         void AtEngage(Unit* target) override;
         void AtDisengage() override;
 
diff --git a/src/server/game/Entities/Unit/Unit.h b/src/server/game/Entities/Unit/Unit.h
index 44b6747242..d9b63020a9 100644
--- a/src/server/game/Entities/Unit/Unit.h
+++ b/src/server/game/Entities/Unit/Unit.h
@@ -1232,10 +1232,10 @@ class TC_GAME_API Unit : public WorldObject
 
         /// ====================== THREAT & COMBAT ====================
         bool CanHaveThreatList() const { return m_threatManager.CanHaveThreatList(); }
-        // This value can be different from IsInCombat:
+        // This value can be different from IsInCombat, for example:
         // - when a projectile spell is midair against a creature (combat on launch - threat+aggro on impact)
         // - when the creature has no targets left, but the AI has not yet ceased engaged logic
-        bool IsEngaged() const { return m_isEngaged; }
+        virtual bool IsEngaged() const { return IsInCombat(); }
         bool IsEngagedBy(Unit const* who) const { return CanHaveThreatList() ? IsThreatenedBy(who) : IsInCombatWith(who); }
         void EngageWithTarget(Unit* who); // Adds target to threat list if applicable, otherwise just sets combat state
         // Combat handling
@@ -2002,11 +2002,12 @@ class TC_GAME_API Unit : public WorldObject
         void ProcessPositionDataChanged(PositionFullTerrainStatus const& data) override;
         virtual void ProcessTerrainStatusUpdate(ZLiquidStatus status, Optional<LiquidData> const& liquidData);
 
+        // notifiers
         virtual void AtEnterCombat() { }
         virtual void AtExitCombat();
 
-        virtual void AtEngage(Unit* /*target*/) { m_isEngaged = true; }
-        virtual void AtDisengage() { m_isEngaged = false; }
+        virtual void AtEngage(Unit* /*target*/) {}
+        virtual void AtDisengage() {}
 
         void InterruptMovementBasedAuras();
     private:
diff --git a/src/server/scripts/Commands/cs_debug.cpp b/src/server/scripts/Commands/cs_debug.cpp
index 8f15f2561e..19f747ddb1 100644
--- a/src/server/scripts/Commands/cs_debug.cpp
+++ b/src/server/scripts/Commands/cs_debug.cpp
@@ -859,7 +859,7 @@ public:
         ThreatManager& mgr = target->GetThreatManager();
         if (!target->IsAlive())
         {
-            handler->PSendSysMessage("%s (GUID %u) is not alive.", target->GetName().c_str(), target->GetGUID().GetCounter());
+            handler->PSendSysMessage("%s (GUID %u) is not alive.%s", target->GetName().c_str(), target->GetGUID().GetCounter(), target->IsEngaged() ? " (It is, however, engaged. Huh?)" : "");
             return true;
         }
 
diff --git a/src/server/scripts/EasternKingdoms/BlackrockMountain/BlackrockDepths/instance_blackrock_depths.cpp b/src/server/scripts/EasternKingdoms/BlackrockMountain/BlackrockDepths/instance_blackrock_depths.cpp
index 83cf8c82fb..045458ce85 100644
--- a/src/server/scripts/EasternKingdoms/BlackrockMountain/BlackrockDepths/instance_blackrock_depths.cpp
+++ b/src/server/scripts/EasternKingdoms/BlackrockMountain/BlackrockDepths/instance_blackrock_depths.cpp
@@ -372,16 +372,9 @@ public:
                 if (Creature* boss = instance->GetCreature(TombBossGUIDs[i]))
                 {
                     if (!boss->IsAlive())
-                    {//do not call EnterEvadeMode(), it will create infinit loops
                         boss->Respawn();
-                        boss->RemoveAllAuras();
-                        boss->CombatStop(true);
-                        boss->GetThreatManager().NotifyDisengaged();
-                        boss->LoadCreaturesAddon();
-                        boss->GetMotionMaster()->MoveTargetedHome();
-                        boss->SetLootRecipient(nullptr);
-                    }
-                    boss->SetFaction(FACTION_FRIENDLY);
+                    else
+                        boss->SetFaction(FACTION_FRIENDLY);
                 }
             }
             GhostKillCount = 0;
diff --git a/src/server/scripts/EasternKingdoms/Karazhan/bosses_opera.cpp b/src/server/scripts/EasternKingdoms/Karazhan/bosses_opera.cpp
index 30e3bb7aae..bd7b5c7117 100644
--- a/src/server/scripts/EasternKingdoms/Karazhan/bosses_opera.cpp
+++ b/src/server/scripts/EasternKingdoms/Karazhan/bosses_opera.cpp
@@ -1253,7 +1253,6 @@ public:
                         Julianne->GetMotionMaster()->Clear();
                         Julianne->setDeathState(JUST_DIED);
                         Julianne->CombatStop(true);
-                        Julianne->GetThreatManager().NotifyDisengaged();
                         Julianne->SetUInt32Value(UNIT_DYNAMIC_FLAGS, UNIT_DYNFLAG_LOOTABLE);
                     }
                     return;
@@ -1528,7 +1527,6 @@ void boss_julianne::boss_julianneAI::DamageTaken(Unit* /*done_by*/, uint32 &dama
                 Romulo->GetMotionMaster()->Clear();
                 Romulo->setDeathState(JUST_DIED);
                 Romulo->CombatStop(true);
-                Romulo->GetThreatManager().NotifyDisengaged();
                 Romulo->SetUInt32Value(UNIT_DYNAMIC_FLAGS, UNIT_DYNFLAG_LOOTABLE);
             }
 
diff --git a/src/server/scripts/EasternKingdoms/ScarletEnclave/the_scarlet_enclave_chapter_5.cpp b/src/server/scripts/EasternKingdoms/ScarletEnclave/the_scarlet_enclave_chapter_5.cpp
index aecf3d32c4..ae29208b64 100644
--- a/src/server/scripts/EasternKingdoms/ScarletEnclave/the_scarlet_enclave_chapter_5.cpp
+++ b/src/server/scripts/EasternKingdoms/ScarletEnclave/the_scarlet_enclave_chapter_5.cpp
@@ -1388,11 +1388,12 @@ public:
                     if (me->HasAura(SPELL_THE_MIGHT_OF_MOGRAINE))
                         me->RemoveAurasDueToSpell(SPELL_THE_MIGHT_OF_MOGRAINE);
                     me->RemoveAllAuras();
-                    me->GetThreatManager().ClearAllThreat();
                     me->CombatStop(true);
                     me->InterruptNonMeleeSpells(false);
                     me->SetWalk(false);
 
+                    EngagementOver();
+
                     for (uint8 i = 0; i < ENCOUNTER_DEFENDER_NUMBER; ++i)
                         DespawnNPC(uiDefenderGUID[i]);
                     for (uint8 i = 0; i < ENCOUNTER_EARTHSHATTER_NUMBER; ++i)
@@ -1408,8 +1409,8 @@ public:
 
                     if (Creature* temp = ObjectAccessor::GetCreature(*me, uiKorfaxGUID))
                     {
+                        temp->AI()->EnterEvadeMode();
                         temp->RemoveAllAuras();
-                        temp->GetThreatManager().ClearAllThreat();
                         temp->CombatStop(true);
                         temp->AttackStop();
                         temp->SetFaction(me->GetFaction());
@@ -1420,7 +1421,6 @@ public:
                     if (Creature* temp = ObjectAccessor::GetCreature(*me, uiMaxwellGUID))
                     {
                         temp->RemoveAllAuras();
-                        temp->GetThreatManager().ClearAllThreat();
                         temp->CombatStop(true);
                         temp->AttackStop();
                         temp->SetFaction(me->GetFaction());
@@ -1430,8 +1430,8 @@ public:
 
                     if (Creature* temp = ObjectAccessor::GetCreature(*me, uiEligorGUID))
                     {
+                        temp->AI()->EnterEvadeMode();
                         temp->RemoveAllAuras();
-                        temp->GetThreatManager().ClearAllThreat();
                         temp->CombatStop(true);
                         temp->AttackStop();
                         temp->SetFaction(me->GetFaction());
@@ -1442,8 +1442,8 @@ public:
 
                     if (Creature* temp = ObjectAccessor::GetCreature(*me, uiKoltiraGUID))
                     {
+                        temp->AI()->EnterEvadeMode();
                         temp->RemoveAllAuras();
-                        temp->GetThreatManager().ClearAllThreat();
                         temp->CombatStop(true);
                         temp->AttackStop();
                         temp->SetFaction(me->GetFaction());
@@ -1457,8 +1457,8 @@ public:
 
                     if (Creature* temp = ObjectAccessor::GetCreature(*me, uiThassarianGUID))
                     {
+                        temp->AI()->EnterEvadeMode();
                         temp->RemoveAllAuras();
-                        temp->GetThreatManager().ClearAllThreat();
                         temp->CombatStop(true);
                         temp->AttackStop();
                         temp->SetFaction(me->GetFaction());
diff --git a/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/hyjalAI.cpp b/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/hyjalAI.cpp
index 004069b7b4..35e9b2d274 100644
--- a/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/hyjalAI.cpp
+++ b/src/server/scripts/Kalimdor/CavernsOfTime/BattleForMountHyjal/hyjalAI.cpp
@@ -423,9 +423,10 @@ void hyjalAI::EnterEvadeMode(EvadeReason /*why*/)
     if (me->GetEntry() != JAINA)
         me->RemoveAllAuras();
     me->CombatStop(true);
-    me->GetThreatManager().NotifyDisengaged();
     me->LoadCreaturesAddon();
 
+    EngagementOver();
+
     if (me->IsAlive())
         me->GetMotionMaster()->MoveTargetedHome();
 
diff --git a/src/server/scripts/Kalimdor/zone_desolace.cpp b/src/server/scripts/Kalimdor/zone_desolace.cpp
index 785d7fd6c2..032184e111 100644
--- a/src/server/scripts/Kalimdor/zone_desolace.cpp
+++ b/src/server/scripts/Kalimdor/zone_desolace.cpp
@@ -85,8 +85,10 @@ public:
 
                     me->UpdateEntry(NPC_TAMED_KODO);
                     me->CombatStop();
-                    me->GetThreatManager().ClearAllThreat();
                     me->SetSpeedRate(MOVE_RUN, 0.6f);
+
+                    EngagementOver();
+
                     me->FollowTarget(caster);
                     me->setActive(true);
                 }
diff --git a/src/server/scripts/Kalimdor/zone_the_barrens.cpp b/src/server/scripts/Kalimdor/zone_the_barrens.cpp
index bce656a1ee..c484040f92 100644
--- a/src/server/scripts/Kalimdor/zone_the_barrens.cpp
+++ b/src/server/scripts/Kalimdor/zone_the_barrens.cpp
@@ -220,9 +220,11 @@ public:
         {
             me->RemoveAllAuras();
             me->CombatStop(true);
-            me->GetThreatManager().NotifyDisengaged();
 
             me->StopMoving();
+
+            EngagementOver();
+
             me->GetMotionMaster()->MoveIdle();
 
             me->SetFaction(FACTION_FRIENDLY_F);
diff --git a/src/server/scripts/Northrend/IcecrownCitadel/boss_icecrown_gunship_battle.cpp b/src/server/scripts/Northrend/IcecrownCitadel/boss_icecrown_gunship_battle.cpp
index d0f98c38e9..aef223ccf6 100644
--- a/src/server/scripts/Northrend/IcecrownCitadel/boss_icecrown_gunship_battle.cpp
+++ b/src/server/scripts/Northrend/IcecrownCitadel/boss_icecrown_gunship_battle.cpp
@@ -579,7 +579,7 @@ struct gunship_npc_AI : public ScriptedAI
             return;
 
         me->CombatStop(true);
-        me->GetThreatManager().NotifyDisengaged();
+        EngagementOver();
         me->GetMotionMaster()->MoveTargetedHome();
     }
 
@@ -724,7 +724,6 @@ class npc_gunship : public CreatureScript
                     Creature* stalker = *itr;
                     stalker->RemoveAllAuras();
                     stalker->CombatStop(true);
-                    stalker->GetThreatManager().NotifyDisengaged();
                 }
 
                 uint32 explosionSpell = isVictory ? SPELL_EXPLOSION_VICTORY : SPELL_EXPLOSION_WIPE;
@@ -883,7 +882,7 @@ class npc_high_overlord_saurfang_igb : public CreatureScript
                     return;
 
                 me->CombatStop(true);
-                me->GetThreatManager().NotifyDisengaged();
+                EngagementOver();
                 me->GetMotionMaster()->MoveTargetedHome();
 
                 Reset();
@@ -1147,7 +1146,7 @@ class npc_muradin_bronzebeard_igb : public CreatureScript
                     return;
 
                 me->CombatStop(true);
-                me->GetThreatManager().NotifyDisengaged();
+                EngagementOver();
                 me->GetMotionMaster()->MoveTargetedHome();
 
                 Reset();
diff --git a/src/server/scripts/Northrend/IcecrownCitadel/boss_the_lich_king.cpp b/src/server/scripts/Northrend/IcecrownCitadel/boss_the_lich_king.cpp
index fd5d510b2f..4268abcfa0 100644
--- a/src/server/scripts/Northrend/IcecrownCitadel/boss_the_lich_king.cpp
+++ b/src/server/scripts/Northrend/IcecrownCitadel/boss_the_lich_king.cpp
@@ -1767,7 +1767,7 @@ class npc_terenas_menethil : public CreatureScript
                     return;
 
                 me->CombatStop(false);
-                me->GetThreatManager().NotifyDisengaged();
+                EngagementOver();
             }
 
             void DamageTaken(Unit* /*attacker*/, uint32& damage) override
diff --git a/src/server/scripts/Northrend/Naxxramas/boss_patchwerk.cpp b/src/server/scripts/Northrend/Naxxramas/boss_patchwerk.cpp
index 66203f440e..31ddcda930 100644
--- a/src/server/scripts/Northrend/Naxxramas/boss_patchwerk.cpp
+++ b/src/server/scripts/Northrend/Naxxramas/boss_patchwerk.cpp
@@ -117,7 +117,7 @@ public:
                         ThreatReference* secondThreat = nullptr;
                         ThreatReference* thirdThreat = nullptr;
 
-                        ThreatManager const& mgr = me->GetThreatManager();
+                        ThreatManager& mgr = me->GetThreatManager();
                         Unit* currentVictim = mgr.GetCurrentVictim();
                         auto list = mgr.GetModifiableThreatList();
                         auto it = list.begin(), end = list.end();
diff --git a/src/server/scripts/Northrend/Nexus/Oculus/boss_urom.cpp b/src/server/scripts/Northrend/Nexus/Oculus/boss_urom.cpp
index 1ea959d370..9f176efa24 100644
--- a/src/server/scripts/Northrend/Nexus/Oculus/boss_urom.cpp
+++ b/src/server/scripts/Northrend/Nexus/Oculus/boss_urom.cpp
@@ -290,7 +290,7 @@ class boss_urom : public CreatureScript
             {
                 me->RemoveAllAuras();
                 me->CombatStop(false);
-                me->GetThreatManager().NotifyDisengaged();
+                EngagementOver();
             }
 
             void SpellHit(Unit* /*caster*/, SpellInfo const* spellInfo) override
diff --git a/src/server/scripts/Northrend/Ulduar/Ulduar/boss_freya.cpp b/src/server/scripts/Northrend/Ulduar/Ulduar/boss_freya.cpp
index 4ef5a170b3..bac96a03ec 100644
--- a/src/server/scripts/Northrend/Ulduar/Ulduar/boss_freya.cpp
+++ b/src/server/scripts/Northrend/Ulduar/Ulduar/boss_freya.cpp
@@ -631,7 +631,7 @@ class boss_freya : public CreatureScript
                         Elder->RemoveAllAuras();
                         Elder->AttackStop();
                         Elder->CombatStop(true);
-                        Elder->GetThreatManager().NotifyDisengaged();
+                        EngagementOver();
                         Elder->AI()->DoAction(ACTION_ELDER_FREYA_KILLED);
                     }
                 }
diff --git a/src/server/scripts/Northrend/zone_borean_tundra.cpp b/src/server/scripts/Northrend/zone_borean_tundra.cpp
index 5efd5a7b9e..1d4c41e05d 100644
--- a/src/server/scripts/Northrend/zone_borean_tundra.cpp
+++ b/src/server/scripts/Northrend/zone_borean_tundra.cpp
@@ -720,7 +720,6 @@ public:
             Creature* owner = GetOwner()->ToCreature();
             owner->RemoveAllAurasExceptType(SPELL_AURA_DUMMY);
             owner->CombatStop(true);
-            owner->GetThreatManager().NotifyDisengaged();
             owner->GetMotionMaster()->Clear(false);
             owner->GetMotionMaster()->MoveFollow(GetCaster(), 4.0f, 0.0f);
             owner->CastSpell(owner, SPELL_SUBDUED, true);
diff --git a/src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_leotheras_the_blind.cpp b/src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_leotheras_the_blind.cpp
index 4daaef7af1..e3938c2b21 100644
--- a/src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_leotheras_the_blind.cpp
+++ b/src/server/scripts/Outland/CoilfangReservoir/SerpentShrine/boss_leotheras_the_blind.cpp
@@ -525,7 +525,7 @@ public:
                 {
                     ThreatManager const& mgr = me->GetThreatManager();
                     std::list<Unit*> TargetList;
-                    Unit* currentVictim = mgr.GetCurrentVictim();
+                    Unit* currentVictim = mgr.GetLastVictim();
                     for (ThreatReference const* ref : mgr.GetSortedThreatList())
                     {
                         if (Player* tempTarget = ref->GetVictim()->ToPlayer())
diff --git a/src/server/scripts/Outland/zone_hellfire_peninsula.cpp b/src/server/scripts/Outland/zone_hellfire_peninsula.cpp
index 5e62d752d6..d13e736c61 100644
--- a/src/server/scripts/Outland/zone_hellfire_peninsula.cpp
+++ b/src/server/scripts/Outland/zone_hellfire_peninsula.cpp
@@ -101,7 +101,7 @@ public:
                 me->SetFlag(UNIT_NPC_FLAGS, UNIT_NPC_FLAG_QUESTGIVER);
                 me->RemoveAllAuras();
                 me->CombatStop(true);
-                me->GetThreatManager().NotifyDisengaged();
+                EngagementOver();
                 Talk(SAY_FREE);
                 return;
             }
@@ -981,7 +981,7 @@ public:
                 me->RestoreFaction();
                 me->RemoveAllAuras();
                 me->CombatStop(true);
-                me->GetThreatManager().NotifyDisengaged();
+                EngagementOver();
                 me->SetFlag(UNIT_NPC_FLAGS, UNIT_NPC_FLAG_QUESTGIVER);
                 me->SetImmuneToPC(true);
                 Talk(SAY_DEFEATED);