Summary:
Powder snow can be pushed or pulled by pistons. In Java Edition, attempting to push powder snow with a piston breaks the block, and attempting to pull it does nothing.

Steps to Reproduce:

1. Place a sticky piston
2. Place a button on the piston
3. Place powder snow in front of the piston
4. Activate the piston

Observed Results:
The powder snow is pushed/pulled by the piston.

Expected Results:
The powder snow should not be pushed/pulled by the piston.

Videos:
Bedrock:
Minecraft 2021-01-02 12-15-12.mp4
Java:
Minecraft 20w51a - Singleplayer 2021-01-02 12-06-22.mp4