diff --git a/src/server/game/Instances/InstanceScript.cpp b/src/server/game/Instances/InstanceScript.cpp
index 58736904a..bb510cf12 100644
--- a/src/server/game/Instances/InstanceScript.cpp
+++ b/src/server/game/Instances/InstanceScript.cpp
@@ -57,23 +57,7 @@ void InstanceScript::SaveToDB()
 
 void InstanceScript::OnPlayerEnter(Player* player)
 {
-    if (!IsTwoFactionInstance())
-        return;
-
-    if (GetTeamIdInInstance() == TEAM_NEUTRAL)
-    {
-        if (Group* group = player->GetGroup())
-        {
-            if (Player* leader = ObjectAccessor::FindConnectedPlayer(group->GetLeaderGUID()))
-                _teamIdInInstance = leader->GetTeamId();
-            else
-                _teamIdInInstance = player->GetTeamId();
-        }
-        else
-            _teamIdInInstance = player->GetTeamId();
-    }
-
-    if (sWorld->getBoolConfig(CONFIG_ALLOW_TWO_SIDE_INTERACTION_GROUP))
+    if (sWorld->getBoolConfig(CONFIG_ALLOW_TWO_SIDE_INTERACTION_GROUP) && IsTwoFactionInstance())
         player->SetFaction((_teamIdInInstance == TEAM_HORDE) ? 1610 /*FACTION_HORDE*/ : 1 /*FACTION_ALLIANCE*/);
 }
 
diff --git a/src/server/game/Instances/InstanceScript.h b/src/server/game/Instances/InstanceScript.h
index 640242fee..89246ed96 100644
--- a/src/server/game/Instances/InstanceScript.h
+++ b/src/server/game/Instances/InstanceScript.h
@@ -285,6 +285,10 @@ public:
     [[nodiscard]] bool AllBossesDone() const;
     [[nodiscard]] bool AllBossesDone(std::initializer_list<uint32> bossIds) const;
 
+    TeamId GetTeamIdInInstance() const { return _teamIdInInstance; }
+    void SetTeamIdInInstance(TeamId teamId) { _teamIdInInstance = teamId; }
+    bool IsTwoFactionInstance() const;
+
     TaskScheduler scheduler;
 protected:
     void SetHeaders(std::string const& dataHeaders);
@@ -325,9 +329,6 @@ protected:
     void WritePersistentData(std::ostringstream& data);
     virtual void WriteSaveDataMore(std::ostringstream& /*data*/) { }
 
-    TeamId GetTeamIdInInstance() const { return _teamIdInInstance; }
-    bool IsTwoFactionInstance() const;
-
 private:
     static void LoadObjectData(ObjectData const* creatureData, ObjectInfoMap& objectInfo);
 
diff --git a/src/server/game/Maps/Map.cpp b/src/server/game/Maps/Map.cpp
index ded8c0c6f..6436f0bda 100644
--- a/src/server/game/Maps/Map.cpp
+++ b/src/server/game/Maps/Map.cpp
@@ -3020,6 +3020,15 @@ bool InstanceMap::AddPlayerToMap(Player* player)
     m_resetAfterUnload = false;
     m_unloadWhenEmpty = false;
 
+    if (instance_data && instance_data->IsTwoFactionInstance()
+        && instance_data->GetTeamIdInInstance() == TEAM_NEUTRAL)
+    {
+        instance_data->SetTeamIdInInstance(player->GetTeamId());
+        if (Group* group = player->GetGroup())
+            if (Player* leader = ObjectAccessor::FindConnectedPlayer(group->GetLeaderGUID()))
+                instance_data->SetTeamIdInInstance(leader->GetTeamId());
+    }
+
     // this will acquire the same mutex so it cannot be in the previous block
     Map::AddPlayerToMap(player);