Horses spawning 1 block in the air

horse spawned and walked around in the air

What I expected to happen was...:
the horse would not be in the air

What actually happened was...:
a horse in a plains biome was walking around in the air, i think it spawned on the grass instead of the grass blocs on the ground

Steps to Reproduce:
1. find plains biome
2. find a horse
3. see if it is walking around in the air