I was building something on a creative world then suddenly I hear a horse taking damage. I take a look around and see this horse under 2 blocks. He kept jumping a little bit as if his head was hitting the roof but he took damage.

What I expected to happen was...:
Him to bounce off the roof and take no damage.

What actually happened was...:
He took damage

Steps to Reproduce:
1. Make an area with a roof and a way out but around the sides, blocks.
2. Spawn a horse in there.
3. Sometimes it will get half out the entrance then try to jump up the block and take damage. This only happened once when I tested it and I didn't get a screenshot
4. Check the screenshots for a tutorial on a testing area that works.