juhhh in case

src/main/java/kamkeel/npcs/controllers/SyncController.java

@@ -272,6 +272,7 @@ public class SyncController {
         SyncHandler handler = SyncRegistry.getHandler(syncType);
         if (handler == null) return;
         try {
+            handler.clientHandleUpdate(compound);
             handler.clientHandleUpdate(compound, id);
             handler.clientHandleUpdate(compound, key);
         } catch (Exception e) {

src/main/java/kamkeel/npcs/controllers/sync/SyncHandler.java

@@ -56,6 +56,20 @@ public interface SyncHandler {
         // No-op: type does not support individual updates
     }
 
+    /**
+     * Handle an UPDATE action on the client.
+     * Deserialize a single object and insert/replace it in the client-side data.
+     *
+     * <p>Default: no-op. Types that don't support individual updates
+     * use {@code syncAll()} for full reload instead.</p>
+     *
+     * @param compound   the serialized single object
+     */
+    @SideOnly(Side.CLIENT)
+    default void clientHandleUpdate(NBTTagCompound compound) {
+        // No-op: type does not support individual updates
+    }
+    
     /**
      * Handle an UPDATE action on the client.
      * Deserialize a single object and insert/replace it in the client-side data.