Put the summary of the bug you're having here

What I expected to happen was...:
Typically there is a slow change or division between biomes, and it does not instantly adapt on the boarder, so I expected a slope down to the bottom of the deep ocean biome.

What actually happened was...:
Instead on the division line the biome had a large strait drop and cut off land immediately, just leaving an open cliff face and riverbed.

Steps to Reproduce:
1) Generate world
2) The bug will generate itself if you explore the edges of biomes