Bats can fly though glass panes.

Spawned bats flew though the corner of a glass pane cage, spawned though creative.

What I expected to happen was...:
Bat stay in the cage.

What actually happened was...:
The bat flew though the corner of the glass pane cage.

Steps to Reproduce:
1. Build a glass pane cage.
2. Spawn bat inside.
3. Close cage
4. Bat glitches though corner.