Put the summary of the bug you're having here
I thought the horse armor would go on the horse no problem.
Instead the horse armor applied and gave me another set of armor.
Steps to Reproduce:
1. Get horse armor.
2. Apply to horse.
3. ...
Linked issues
is duplicated by 5
MC-13743
Right clicking an armored horse with horse armor wil drop horse armor
Resolved
MC-13752
horse
Resolved
MC-13933
Horse Armor/Saddle Glitch
Resolved
MC-14160
Duplicates of Horse Armor
Resolved
MC-14762
Horse armor being replaced on horse when it is the same type of armor causing item drop
Resolved
Did you do this in creative or survival? It's likely that if you're in creative, it's just creating doing its thing and not using up the item. The armour should then pop off the horse as well because you may want to change it.