Some lakes in frozen biomes generate unfrozen

The bug

Upon world generation within snowy biomes, lakes that have water surfaces exposed to sunlight are sometimes not frozen over. This can either happen for the whole lake if it is within a chunk, or along chunk borders if it is between chunks. It doesn't seem to be dependent on 8x8 chunk sections as it is described in MC-125007.

How to reproduce

1. Generate new world
2. Locate igloo or find some way to go to a snowy biome
3. Observe surface lakes until one is found in this condition