Occasional blocks in Frozen Ocean biomes rain instead of snow. Ice does not form, nor do snow layers form on solid blocks placed there.

This is unrelated to Deep Frozen Ocean.

Has been reproduced on multiple seeds. The following is a quick way to reproduce:

Create world with seed: -4610570334085788167, go to -1164, 64, -3982, set weather to rain.

Expected: Snow in all blocks marked as Frozen Ocean biome.

Observed; Snow in almost all blocks marked as Frozen Ocean biome, and some blocks show rain.