--- a/server/world/hideout_engine.py
+++ b/server/world/hideout_engine.py
@@ -267,13 +267,18 @@
     def enter_map_portal(
         self,
         player_id: str,
-        portal_index: Optional[int] = None
+        portal_index: Optional[int] = None,
+        zone_engine: Optional[Any] = None,
     ) -> Tuple[bool, str, Optional[Dict[str, Any]]]:
         """
         Enters an active Map Device portal.
         Consumes exactly 1 portal from the remaining 6 charges.
         When 0 portals remain, the map instance is sealed permanently.
         """
+        if portal_index is not None and not isinstance(portal_index, int) and zone_engine is None:
+            zone_engine = portal_index
+            portal_index = None
+
         hideout = self.get_or_create_hideout(player_id)
         dev = hideout.map_device
 
@@ -310,9 +315,13 @@
             "portal_index": target_idx,
         }
 
-        # If exhausted all 6 portals, close device
+        # If exhausted all 6 portals, close device and purge instance session from ZoneEngine
         if dev.portals_remaining == 0:
+            if zone_engine is not None and hasattr(zone_engine, "active_instances"):
+                if dev.active_instance_id and dev.active_instance_id in zone_engine.active_instances:
+                    zone_engine.active_instances.pop(dev.active_instance_id, None)
             dev.active_map = None
+            dev.active_instance_id = None
             msg = f"Đã bước qua cổng #{target_idx + 1}. Đây là CỔNG CUỐI CÙNG (0/6)! Tinh Đồ Nghi đã khép lại."
         else:
             msg = f"Đã bước qua cổng #{target_idx + 1}. Còn lại {dev.portals_remaining}/6 Cổng Tinh Đồ."
--- a/tests/unit/test_hideout_engine.py
+++ b/tests/unit/test_hideout_engine.py
@@ -116,6 +116,10 @@
     assert res_last is not None
     assert res_last["portals_remaining"] == 0
     assert "CỔNG CUỐI CÙNG" in msg_last
+    hideout = engine.get_or_create_hideout(player_id)
+    assert hideout.map_device.active_map is None
+    assert hideout.map_device.active_instance_id is None
+    assert hideout.map_device.portals_remaining == 0
 
     # 7th attempt must be rejected (all 6 portals exhausted)
     ok_fail, msg_fail, res_fail = engine.enter_map_portal(player_id)
@@ -264,6 +268,25 @@
     assert zone_engine.can_spawn_hostile_monsters("zone_player_hideout") is False
     assert zone_engine.can_spawn_hostile_monsters("zone_blood_scale_ruins") is True
 
+    # Enter first 5 portals with zone_engine
+    for _ in range(5):
+        ok_enter, _, _ = engine.enter_map_portal(player_id, zone_engine=zone_engine)
+        assert ok_enter is True
+        assert inst_id in zone_engine.active_instances
+
+    # Enter 6th and final portal
+    ok_final, msg_final, res_final = engine.enter_map_portal(player_id, zone_engine=zone_engine)
+    assert ok_final is True
+    assert res_final['portals_remaining'] == 0
+    assert "CỔNG CUỐI CÙNG" in msg_final
+
+    # Assert instance unregistered from ZoneEngine and active_instance_id cleared
+    assert inst_id not in zone_engine.active_instances
+    dev = engine.get_or_create_hideout(player_id).map_device
+    assert dev.active_instance_id is None
+    assert dev.active_map is None
+    assert dev.portals_remaining == 0
+
 
 def test_client_hideout_gates_dynamic_tier_binding() -> None:
     """Verifies client hideout_gates.js defines MAP_TIER_CONFIGS and dynamic setMapTier."""