If another language than English is selected in the Minecraft Client, in Multiplayer there all Items get renamed to the selected language. There is a wrong amount of needed XP shown when trying to use it.
(Client thinks that you don't rename, server says that you rename your item -> Using the Anvil doesn't work, original items drop)
Duplicate of MC-1123, please use the search function to see if your bug has already been submitted. Currently over 50% of tickets are being closed as duplicate.