Snow/Snow Blocks override grass on a dirt block

This snapshot has grass blocks under snow (which gain the snow-sided texture) returning to plain dirt blocks as they would if they were under any normal block. I assume this is unintended behavior. Tested it in 19w12b and it is not occurring, so it is only in this snapshot. Does not seem to be a biome related issue either, tested it in biomes both where snow naturally and does not naturally occur.