Duplicating Horses.

What I expected to happen was...:
I expected to return to my house on my house, and I hoped that nothing would happen.

What actually happened was...:
When I got to my house, I found another horse in the exact same place where I left off. The amazing part is that it had the saddle and horse armor on it as well.

Steps to Reproduce:
1. Make a pen for a horse (I had no leads.).
2. Ride your horse far enough away so that your house is out of render distance.
3. Come back and see the cloned horse.
(DISCLAIMER: I am not even sure if this explanation works, but it is how it happened. Also, this has happened more than once.)