ScriptableObject error with Inheritance

here is the error i recieve:

the error is on this line.:

 if (pItem.isStackable)
 {
 }

I should note that the error only occurs when I build the game. It does not occur when I run the game in the editor.

I believe the error comes from trying to give the player a weapon in their inventory.

because this runs fine:

 Player.playerInv.AddItem(apple);

and this doesn't:

  Player.playerInv.AddItem(sword2);

the only difference is apple is an item and Sword2 is a weapon... I have reason to believe that the build is expecting an Item to be loaded and not a weapon. (Weapon is a child of item. item inherits ScriptableObject).

here is the code for weapons and items (sorry for large file):

 using System;
 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 
 [CreateAssetMenu(fileName = "Item", menuName = "StrangeEngine/Item", order = 2)]
 public class Item : ScriptableObject
 {
     public enum ItemType
     {
         Item = 1,
         Skill = 2,
         Equipment = 3
     }
     public ItemType type;
     public int ID;
     public string itemName;
     public string info;
     public int worth;
     public bool isStackable = false;
     //public Sprite icon;
     public Dictionary<string, int> itemStats = new Dictionary<string, int>(); // "stats" that come in pairs, a name (string) and a number. for example ("weight", 22)
 
     public Item(ItemType pType, int pID, string pName, string pInfo, int pWorth, Dictionary<string,int> pStats)
     {
         type = pType;
         ID = pID;
         itemName = pName;
         info = pInfo;
         worth = pWorth;
         itemStats = pStats;
     }
     public Item(ItemType pType, int pID, string pName, string pInfo, int pWorth, Dictionary<string, int> pStats, bool pIsStackable)
     {
         type = pType;
         ID = pID;
         itemName = pName;
         info = pInfo;
         worth = pWorth;
         itemStats = pStats;
         isStackable = pIsStackable;
     }
 }
 
 [CreateAssetMenu(fileName = "Item", menuName = "StrangeEngine/Weapon", order = 3)]
 public class Weapon : Item
 {
     public int Damage;
     public GameObject WeaponModelPrefab;
 
 
     public Weapon(int pID, string pName, string pInfo, int pWorth, Dictionary<string, int> pStatsfloat, int pDamage, GameObject pWeaponPrefab) : base(ItemType.Equipment,pID, pName, pInfo,pWorth,pStatsfloat)
     {
         Damage = pDamage;
         WeaponModelPrefab = pWeaponPrefab;
     }
 }