Horse + Hill Glitch

Put the summary of the bug you're having here

What I expected to happen was...:
My horse to go up the hill easily as I was riding it.

What actually happened was...:
It got stuck and glitched, it did go up but now smoothly and it took longer.

Steps to Reproduce:
1. Get a horse & tame it.
2. Try and ride it up a hill.
3. ...