specify inventory changes

src/main/java/carpet/mixins/Inventory_scarpetEventMixin.java

@@ -27,10 +27,11 @@ public abstract class Inventory_scarpetEventMixin
         if (!PLAYER_PICKS_UP_ITEM.isNeeded() || !(player instanceof ServerPlayer))
             return playerInventory.add(-1, stack);
         int count = stack.getCount();
+        ItemStack previous = stack.copy();
         boolean res = playerInventory.add(-1, stack);
         if (count != stack.getCount()) // res returns false for larger item adding to a almost full ineventory
         {
-            ItemStack diffStack = stack.copyWithCount(count - stack.getCount());
+            ItemStack diffStack = previous.copyWithCount(count - stack.getCount());
             PLAYER_PICKS_UP_ITEM.onItemAction((ServerPlayer) player, null, diffStack);
         }
         return res;