fix(Core/Grids): Grid improvements (#20955)

src/server/game/Maps/MapInstanced.cpp

@@ -203,6 +203,7 @@ InstanceMap* MapInstanced::CreateInstance(uint32 InstanceId, InstanceSave* save,
 
     InstanceMap* map = new InstanceMap(GetId(), InstanceId, difficulty, this);
     ASSERT(map->IsDungeon());
+    m_InstancedMaps[InstanceId] = map;
 
     map->LoadRespawnTimes();
     map->LoadCorpseData();
@@ -212,10 +213,11 @@ InstanceMap* MapInstanced::CreateInstance(uint32 InstanceId, InstanceSave* save,
     else
         map->CreateInstanceScript(false, "", 0);
 
+    map->OnCreateMap();
+
     if (!save) // this is for sure a dungeon (assert above), no need to check here
         sInstanceSaveMgr->AddInstanceSave(GetId(), InstanceId, difficulty);
 
-    m_InstancedMaps[InstanceId] = map;
     return map;
 }
 
@@ -237,10 +239,13 @@ BattlegroundMap* MapInstanced::CreateBattleground(uint32 InstanceId, Battlegroun
 
     BattlegroundMap* map = new BattlegroundMap(GetId(), InstanceId, this, spawnMode);
     ASSERT(map->IsBattlegroundOrArena());
+    m_InstancedMaps[InstanceId] = map;
+
     map->SetBG(bg);
     bg->SetBgMap(map);
 
-    m_InstancedMaps[InstanceId] = map;
+    map->OnCreateMap();
+
     return map;
 }