The bug

Deep Warm Ocean biome isn't availade when creating a "Single Biome", "Caves" or "Floating Islands" world but all other ocean biomes (including the deep variants) are availade.

How to reproduce

Simply create a "Single Biome", "Caves" or "Floating Islands" world and you can see that the "Deep Warm Ocean" biome isn't availade. And the "Warm Ocean" is availade too !!