When in spectator mode, sometimes powder snow will z-fight with blocks placed directly adjacent to it.

How to reproduce:

1. Create a void-type world
2. Run the command /fill ~ ~ ~ ~10 ~10 ~10 minecraft:powder_snow
3. A cube of powder snow will be created
4. Place blocks at random positions along the surface of the powder snow
5. Spectate the inside of the powder snow
6.  When moving at least 7-8 blocks away from any wall, the blocks placed there will start to z-fight