Very small biomes less than 4 by 4 by 4 blocks. 3D biomes change between warm oceans, ocean, rivers, lushcaves, etc. up and down from bedrock to build limit

I was testing the newest snapshot and found a very small warm ocean biome, less than a 4 by 4 blocks, sometimes 4 by 4 by 4. The 3D biomes change between warm ocean, ocean and back with some lush caves in between or a river in the middle of a lukewarm ocean smaller than a 4 by 4, change between biomes between the two biomes with rivers every few blocks up or down from bedrock to build limit

What I expected to happen was...:
Be a bigger Biome

What actually happened was...:
A very small warm ocean(less than 5 by 5 blocks in the middle of an ocean. In spectator the 3D biomes change between warm ocean, ocean and back with some lush caves in between 

Steps to Reproduce:
1. My world was created on Java 1.13 and updated trough multiple updates.

2. Seed is 4876611369082725821.

3. Biomes

   a. Warm Ocean to Ocean 3D biome: coords -3325 63 73

   b. Lukewarm Ocean to River 3D biome: coords -3243 63 -276