rabbits spawning on the edge of the blocks in the mountains

Put the summary of the bug you're having here

What I expected to happen was...:
I expected the rabbit to spawn normally

What actually happened was...:
The rabbit was born on the edge of a block and stuck there.

Steps to Reproduce:
1. Try to create an world that you spawn on an mountain
2. look around for an rabbit
3. The rabbit will likely be trapped on the edge of the snow block.