Anvil Bug, Server renames items while using other languages than English

I can't combine Items on a Server by using an Anvil.
If I combine them I have the new Item until I escape the Anvil Gui
then the Items I wanted to combine are thrown automatically on the ground but my XP are still taken away until I relog in the game
I'm playing on german language and that may be the reason for this strange behaviour, I think, because it doesn't happen on English language
It seems to be the case that the server thinks that I changed the Item name but I haven't its just the german one for the item (I haven't changed it)
the server tries to take 7 exp more for changing the name but he can't because I just have 30 and 37 isn't possible therefore the items are thrown on the ground