For a comprehensive list of other examples of issues with 2D planes in models not being mirrored as expected, click here.
The planes composing powder snow do not mirror on the back as one would expect, resulting in physical/illogical weirdness.
Fixed model (Mojang has full permission to use this fix): powder_snow.json
- Place a powder snow block
- View the cross on the texture as shown in the screenshots
- View the exact same section of that texture plane on the direct opposite side
- Note that the exact texture pattern at that position is different, even though it should be the same