When repairing items in the crafting bench, not anvil, the items will merge the two durabilities, but keep the items in the bench allowing for unlimited duplication.
MC-47322
Item Duplication when repairing items
Resolved
Duplicate
0
54th Duplicate of MC-46715 - If you have not, please use the search function in the future, to see if your bug has already been submitted. If you could not find the original report, please comment with the keywords you searched for.