Custom frozen biomes fail to generate most of the snow/ice when they generate if the precipation is set to "snow" and temperature modifier set to "frozen"

The bug

Custom frozen biomes do not generate snow everywhere.

Seed & Coordinates

The seed is: -4158863989

Coordinates are:  1110 138 -1438

Additional info

The Snowy Jungle from the zip folder does not generate, (intentionally) but if you create a world with the Snowy Jungle, it also fails to generate half of the snow and even rains there.