I used chatGPT to write this script and it works fine in the playmaker's action. But I found that when adding items with CanCarryMultiple, it adds a new separate item instead of increasing the quantity of the same item in the same slot. What should I do?

using UnityEngine;   
using HutongGames.PlayMaker;
using AC;

[ActionCategory("Adventure Creator")]
[UnityEngine.Tooltip("Adjusts the amount of a specific inventory item in Adventure Creator.")]
public class AdjustInventoryAmountAction : FsmStateAction
{
    [RequiredField]
    [UnityEngine.Tooltip("The ID of the inventory item to adjust.")]
    public FsmInt itemID;

    [UnityEngine.Tooltip("The amount to adjust. Positive to add, negative to subtract.")]
    public FsmInt amountToAdjust;

    public override void OnEnter()
    {
        // Get the current inventory item
        InvItem inventoryItem = KickStarter.inventoryManager.GetItem(itemID.Value);

        if (inventoryItem != null)
        {
            if (amountToAdjust.Value > 0)
            {
                // Increase the item count
                KickStarter.runtimeInventory.Add(itemID.Value, amountToAdjust.Value);
            }
            else if (amountToAdjust.Value < 0)
            {
                // Decrease the item count
                KickStarter.runtimeInventory.Remove(itemID.Value, Mathf.Abs(amountToAdjust.Value));
            }
        }
        else
        {
            Debug.LogError("Inventory item with ID " + itemID.Value + " not found.");
        }

        Finish();
    }
}