fix(Core/Maps): fix pooled creature/GO respawn in instanced maps (#25826)

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

src/server/game/Maps/Map.cpp

@@ -2717,13 +2717,19 @@ void Map::ProcessRespawns()
 
 void Map::ProcessCreatureRespawn(ObjectGuid::LowType spawnId)
 {
-    // Pool members are handled entirely by PoolMgr
+    // Pool members in non-instanced maps are handled entirely by PoolMgr.
+    // In instanced maps the pool system operates globally and Spawn1Object is
+    // a no-op for instanceable maps, so fall through to the normal per-instance
+    // respawn logic instead.
+    if (!Instanceable())
+    {
         if (uint32 poolId = sPoolMgr->IsPartOfAPool<Creature>(spawnId))
         {
             sPoolMgr->UpdatePool<Creature>(poolId, spawnId);
             RemoveCreatureRespawnTime(spawnId);
             return;
         }
+    }
 
     CreatureData const* data = sObjectMgr->GetCreatureData(spawnId);
     if (!data)
@@ -2778,13 +2784,17 @@ void Map::ProcessCreatureRespawn(ObjectGuid::LowType spawnId)
 
 void Map::ProcessGameObjectRespawn(ObjectGuid::LowType spawnId)
 {
-    // Pool members are handled entirely by PoolMgr
+    // Same rationale as ProcessCreatureRespawn: pool management via PoolMgr is
+    // only meaningful for non-instanced maps where Spawn1Object actually spawns.
+    if (!Instanceable())
+    {
         if (uint32 poolId = sPoolMgr->IsPartOfAPool<GameObject>(spawnId))
         {
             sPoolMgr->UpdatePool<GameObject>(poolId, spawnId);
             RemoveGORespawnTime(spawnId);
             return;
         }
+    }
 
     GameObjectData const* data = sObjectMgr->GetGameObjectData(spawnId);
     if (!data)