UMG item tutorial crashes when load or restart map

Hello! I just noticed this. I used the tutorial as a guide in my game. Now when the time was to do load/save system in the game i noticed that the game crashes if you have item in your inventory.

If you play and dont pickup anything you can load without problem. If you pick up item and then load it crashes and says this:

The tutorial i am talking about is this: - YouTube

Any change to get a guide to fix this? Thanks.