Put the summary of the bug you're having here

What happened before was
My pickaxe enchanted with Durability I (or whatever it is) broke and vanished from the hotbar like it should.

What I expected to happen was...:
My next pickaxe to go to slot 1 after I shift-clicked it (the only empty one on the hotbar)

What actually happened was...:
When I shift-clicked the new pickaxe, it remained in its original location, and my broken Durability pickaxe reappeared in slot one with its use bar completely empty. When I used it again, it promptly broke, so I tried shift clicking my next one down and again it replicated. Then, after this one broke, I could finally shift-click my pickaxe down like usual.

Steps to Reproduce:
1. Enchant a durability I iron pickaxe
2. Mine until it breaks with another pickaxe in inventory
3. As soon as it breaks tab open inventory and shift-click down the unused iron pickaxe
4. Enjoy the final use in your rematerialized pickaxe.