I put a shovel in an enchanting table for a level 14 enchant and 3 lapis. it took the lapis and only 3 levels, And still gave me the enchant.

I also did this with a pic. I put in two lapis and clicked level 8 enchant and it took away the lapis and only 2 levels. My theory is that a data tag got messed up while the game was being programmed and someone (#IBlameDinnerbone) accidentally put the lapis number as the level number.

A few more interesting things to note: It was hosted on LAN in survival with cheats off, and I was playing with my sister. She experienced it as well.