Snow Covers Melt Without Reason

I placed snow covers in a biome that does not naturally have snow (Not a desert) and the snow covers that were sufficiently away from any light source melted anyways.

What I Expected To Happen Was:
The snow covers that were sufficiently away form all light sources would remain.

What Actually Happened Was:
They Melted Anyways.

Steps To Reproduce:
1. Place snow covers in a biome without natural snow and away from snow melting light sources
2. Wait
3. Witness the unjustified melting of the snow