I was repairing an item on an anvil and when I clicked on it with [ZL], the item’s durability bar disappeared. It was not fully repaired, in which the durability bar would not have shown. This does not just happen on anvils, it happens with any interfaces. 

How to reproduce:

1. /give @s anvil
2. /give @s planks 12
3. /give @s wooden_axe
4. Place the planks.
5. Destroy them with the wooden axe. 
6. Place the anvil. 
7. Enter the anvil interface. 
8. Click on the wooden axe with your right clicker/left trigger. 

Expected results: The durability bar should still be shown.

Observed results: The durability bar disappears.