Moving between different biomes will have rough sky transitions instead of having a smooth sky transition, regardless the biome blend setting

The bug

Moving between different biomes will have rough sky transitions instead of having a smooth sky transition, regardless the biome blend setting.

How to reproduce

1. Use the seed 8030129256475430377
2. Move between 245;1627 and 245;1628 (river and desert biomes)
   → The transition is a rough eye ache instead of a slow and smooth transition.

Note: I expected that biome blend would affect how the sky looks between biomes, or that passing a biome boundary will change the color of the sky slowly.

Example