New Texture Pack system bug

The textures of blocks and most of the items in Snapshot 13w02a seems to have a strange bug.

What I expected to happen was...:

Generating a new world or playing to an actual world on Minecraft 13w02a would have the good textures..

What actually happened was..:

Textures doesn't work for most thing in minecraft 13w02a (except mobs?).

Steps to Reproduce:
1)Install minecraft snapshot 13w02a.
2)Open Minecraft
3)Generate a new world
4)The bug should appear easily...