When glow lichen is on top of a shulker box (no matter the angle), it can still be opened.
- Place down a shulker box facing upwards.
- Place down a glow lichen on top of the shulker box.
- Attempt to open the shulker box.
→ Notice how shulker boxes can be opened when blocked by glow lichens.
The expected behavior would be that shulker boxes cannot be opened when blocked by glow lichens.