Summary:

The upper side of the shulker box fits into powder snow, thereby replacing the inside of the powder snow side.

This bug is not present in the Java version.

Steps to reproduce:

First option

1. Place the shulker box.
2. Place powder snow on top of the shulker box (two blocks high).
3. Enter powder snow.
4. Look at the underside of the inside of the powder snow.

Second option

1. Place the shulker box with the top horizontally (sideways).
2. Place powder snow two blocks high (on the side of the top of the shulker box).
3. Enter powder snow.
4. Look at the side where the shulker box is.

Observed results:

The shulker box is included in powder snow, thereby replacing the powder snow side.

Expected results:

The side should not go into powder snow.

Video:

First option 2021-03-15 11-24-54.mp4

Second option 2021-03-15 11-25-24.mp4

Image: