Killing A Horse Wearing Leather Armor Duplicates The Armor

Whenever you put a piece of dyed leather horse armor onto a horse, and then kill the horse, it will drop two sets of the dyed armor. It happens about 80-90% of the time from what i have seen.

How to reproduce:
1. Tame a horse
2. Dye some leather armor and put it on the horse
3. Kill the horse
4. Repeat until you see it drop two sets of armor

Killing it with a looting sword may as have an affect on the armor duplication.