Horses Can't Naturally Climb

I was in my survival world, and excited to have a faster form of transportation. I had just found a saddle and some iron horse armor from a dungeon. I found a horse and equipped the saddle and horse armor. However, I was unable to automatically climb inclines as horses should. The horse flickered and I raised up as if the horse had actually raised up, too. The horse travels up inclines normally about half the time and the other half it stops on the inclines.

I expected the horse to run up the 1 block incline at top speed.

What actually happened was the horse stopped moving, began flickering, and I raised up for a few seconds as if the horse had raised up. After a few seconds of this, the horse resumed normally.

(The picture shows me raised above the horse, with the horse visible, but still flickering)