When a Copper Golem attempts to place an item in a chest, it will only do so if that item is already in the chest (or the chest is empty). However, when it checks if that item is in the chest already, it checks the exact durability and will only place it in if the durability matches.
Steps to Reproduce:
Place down a wooden chest and spawn a copper golem
Obtain two of the same item with different durabilities
Place one of the items in the wooden chest and one in the copper chest
Observe how the copper golem won’t place the item in the wooden chest if it has a different durability
Expected Result:
The Copper Golem should not care about durability
Can confirm. Found this same bug in my own experiments.