What I expected to happen was...:
Riding a horse, in single player, towards various one block high edges and natural terrain, expecting it to automatically climb.

What actually happened was...:
Roughly 90% of the time, my horse will get stuck and jitter in place on one block high edges. Stubbornly continuing to walk forward will eventually damage the horse. If not damaged, dismounting will apply the expected amount of damage to the horse it would have taken.

Steps to Reproduce:
1. Mount a horse
2. Walk towards a one block high step, causing the horse to get stuck and jitter. Horse may take damage.
3. Repeat step 2 multiple times
4. Dismount, horse may take damage