Whenever I try to anvil something, it combines it, but when I hit ESC, the two things I try to combine just fall on the floor and the exp is gone, but I get it back once I relog. I have tried using a new anvil, and relogging. Nothing is working and it is hurting my anvil business. http://imgur.com/Bh5x0,V252J,8R65d,Bl0YB,PfYuc
After further testing with 4 different items, I can reproduce this but only to a 25% rate, meaning it didnt work each time but did sometimes, I reproduced the bug with a Eff 3 book, and a wooden pickaxe. All other items worked fine. Items i tested: Eff3 book - Wpickaxe = Didnt work Unb3 book - Dpickaxe = Worked Eff4 + Eff 4 dpick = Worked Unb 3 + Eff 4 Dpick = Worked After trying the Wooden pick again, with another book it worked, I believe this may just be a minecraft bug, however could also be plugin related.
This bug has existed since 1.4.6 me and jakeyray18 found it on the first day no one has ever found a fix, it just happens sometimes when combining books with tools, not sure why.
It seems to be a visual error in the amount of levels the anvil shows that you need. Just get around 5-10 more levels than what it says and it should work.