New caves generating with new mountains creates a nice frozen cave

In the most recent version, I found something that I'll be assuming is a bug (but it does look really nice as a cave biome) where a new cave generating into a new mountain will contain snow, powdered snow, ice and frozen lakes. This can be found specifically on seed 868550010 and is a feast for the eyes. To replicate, literally just find any new mountain with a new cave carving into the side of it and you will be able to access this. Screenshots below picture this wonderful bug which has graced the new mountains with it's presence. 

Notes: The generation changes based on which sub-biome is above the cave. Mountain meadows will generate with dirt and grass too.