Core/Maps: Fixed crash caused by using invalid coordinates

Closes #12532

src/server/game/Entities/Object/Object.cpp

@@ -2635,7 +2635,6 @@ void WorldObject::MovePositionToFirstCollision(Position &pos, float dist, float
     float destx, desty, destz;
     destx = pos.m_positionX + dist * std::cos(angle);
     desty = pos.m_positionY + dist * std::sin(angle);
-    destz = NormalizeZforCollision(this, destx, desty, pos.GetPositionZ());
 
     // Prevent invalid coordinates here, position is unchanged
     if (!Trinity::IsValidMapCoord(destx, desty))
@@ -2644,6 +2643,7 @@ void WorldObject::MovePositionToFirstCollision(Position &pos, float dist, float
         return;
     }
 
+    destz = NormalizeZforCollision(this, destx, desty, pos.GetPositionZ());
     bool col = VMAP::VMapFactory::createOrGetVMapManager()->getObjectHitPos(GetMapId(), pos.m_positionX, pos.m_positionY, pos.m_positionZ + 0.5f, destx, desty, destz + 0.5f, destx, desty, destz, -0.5f);
 
     // collision occured