"On item broken" procedure not working with items broken by hitting entities???

I have an "On item broken" procedure which checks if the item broken was a specific item, and if it is, it replaces it with a new item (by setting the item in your hand to the new one). It works when I use the last durability to break a block, but not if I use it to kill entities with the last durability left of the item. The worst part is that this item is a weapon meant to kill things!!! Is this a bug with mcreator or simply me messing up?