I was revisiting a bug that was in 31c that was fixed, enchanted books were spawning in dungeons, strongholds, etc, without enchantments. I believe it was fixed in 32c, but it is still here in 33b. Just load a world in 33b and locate a generated chest containing an enchanted book (upping dungeon rates will make this quicker), and scroll over the book. There won't be an enchantment on it, making it a useless item.

Here's what it looks like: https://i.imgur.com/aleLXHq.png