Core/Quests: Fix an issue where auto-completed quests would not be automatically completed if the quest was added through either the SmartAI action_type SMART_ACTION_ADD_QUEST, the spell effect SPELL_EFFECT_QUEST_START or the opcode CMSG_QUEST_CONFIRM_ACCEPT. Also fixes auto-complete quests in the SAI and opcode case not calling the AI hook.

src/server/game/Handlers/QuestHandler.cpp

@@ -483,7 +483,7 @@ void WorldSession::HandleQuestConfirmAccept(WorldPacket& recvData)
             return;
 
         if (_player->CanAddQuest(quest, true))
-            _player->AddQuest(quest, NULL);                // NULL, this prevent DB script from duplicate running
+            _player->AddQuestAndCheckCompletion(quest, NULL); // NULL, this prevent DB script from duplicate running
 
         _player->SetDivider(0);
     }