Assets/_Project/Scripts/Gameplay/TowerInstance.cs

@@ -1,4 +1,5 @@
 // Assets/_Project/Scripts/Gameplay/TowerInstance.cs
+using System.Collections.Generic;
 using Unity.Netcode;
 using UnityEngine;
 using TD.Core;
@@ -511,11 +512,20 @@ namespace TD.Gameplay
                 ? resolvedDefinition.FootprintSize
                 : new Vector2Int(2, 2);
 
+            // Collect the footprint, then stamp walkability as a BATCH so a single
+            // OnWalkabilityChanged fires for the whole footprint. Per-tile SetWalkable fires
+            // that event once PER TILE — on despawn (sell) that meant up to 4 full enemy A*
+            // re-paths for a 2×2 tower in one frame, which was the sell hitch. Placement
+            // batches for the same reason (TowerPlacementManager.StampWalkable). Occupancy
+            // doesn't fire walkability events, so it stays per-tile.
+            var footprint = new List<Vector2Int>(footprintSize.x * footprintSize.y);
             foreach (var tile in GridCoordinates.GetFootprintTiles(anchorTile.Value, footprintSize))
             {
-                loader.SetWalkable(tile, walkable);
+                footprint.Add(tile);
                 loader.SetOccupied(tile, occupied);
             }
+
+            loader.SetWalkableBatch(footprint, walkable);
         }
 
         // Reused per-instance across color updates to avoid per-call GC allocation.

Assets/_Project/Scripts/Gameplay/TowerPlacementManager.cs

@@ -365,10 +365,27 @@ namespace TD.Gameplay
             PlaySellEffectRpc(worldPos);
         }
 
+        // One-time guard so a missing spawner warns once per peer instead of on every sale.
+        private static bool s_warnedNoSellSpawner;
+
         [Rpc(SendTo.Everyone)]
         private void PlaySellEffectRpc(Vector3 worldPos)
         {
-            SellEffectSpawner.Instance?.Play(worldPos);
+            var spawner = SellEffectSpawner.Instance;
+            if (spawner == null)
+            {
+                if (!s_warnedNoSellSpawner)
+                {
+                    Debug.LogWarning("[TowerPlacementManager] A tower was sold, but there is no " +
+                                     "SellEffectSpawner in the scene — no coin VFX or sell sound " +
+                                     "will play. Add a SellEffectSpawner GameObject to each Match " +
+                                     "scene (assign its Sell Sound clip; the coin burst works even " +
+                                     "with no VFX prefab).");
+                    s_warnedNoSellSpawner = true;
+                }
+                return;
+            }
+            spawner.Play(worldPos);
         }
 
         // ----- Server-side commit hooks called by Builder ------------------