Can't jump on one kind of horses.

Can't jump on one kind of horses.

What I expected to happen was to successfully jump on this horse
I thought that i could jump the same kind of horse.

What actually happened was that I tried to make the horse jump he pushed me out.

The horse pushed me when I tried to make him jump.

Steps to Reproduce:
1. Put this seed in creative (no flat world - normal world) : 6020859745272078623.
2. Go to x= 4.1 y= 65 z=51.7 .
3. Then try to jump the horse in the picture after taming him.