I wanted to see what the cost was, so i put myself into creative and this is what it's costing me, 65 levels for an Iron fortune III pickaxe. Is this actually supposed to happen?
This is the same for any "Block" that can be placed after naming in an anvil.
Just found this out as well.
I too have this problem. the game hangs on a "Converting World" screen/
I can confirm this is happening in my single player game as well.