When using a spawner that spawns multiple types of items the game seems to crash giving the following errors. I have managed to recreate this crash off of 4 different mob spawners 4 different times. All of witch worked in the previous snapshot 13w06a. When playing with 13w07a the game crashed but downgrading back to 13w06a allows the game to run perfectly fine. I have included a .schematic file that can be used to replicate the crash.