Im not sure if this is a bug or maybe just the new enchanting mechanics. I get to level 30 and then enchant a book or tool using the enchanting table. I put the lapis and the tool in the bench and it says the cost (of the third option) is 30 levels. I click that option and my levels only go down to 27. aka it only took away 3 levels.
Linked issues
Comments 3
Duplicate of MC-44481 - If you have not, please use the search function in the future, to see if your bug has already been submitted. If you could not find the original report, please comment with the keywords you searched for.
That is the new design, the Wiki has more details on the gameplay mechanics of it.