Summary:
While inside powder snow, you cannot summon a mob with a spawn eggs. It also violates parity with the Java version.

Steps to reproduce:

1. Place 2 blocks of powder snow vertically.
2. Get a spawn egg (any mob).
3. Go inside powder snow.
4. Try to summon a mob with a spawn egg.

Observed results:
You cannot use a spawn egg inside powder snow.

Expected results:
The player can summon a mob inside powder snow using a spawn egg.