What I expected to happen was...:
I was starting up a normal Minecraft single player. I created a new world for the snapshots to get some experience over the upcoming 1.9 update.

What actually happened was...:
But when I got to play, the Savanna Biome was doing weird stuff. Blocks were going from underground to the sky, some blocks were invisible, and villagers i found were also invisible.

Steps to Reproduce:
1. Start a new snapshot 15w37a -world
2. Find Savanna-Biome
3. Seed is 7242249954336383171
4. Some screenshots about what happened in the screenshot 15w37a as attachment below
5. No mods or resource packs used.