Invisible Villager Armor

When putting armor on villagers using a dispenser, the armor is there but dose not show. But mob heads and pumpkins do. Link to video showing this by cubfan135: https://www.youtube.com/watch?v=DC-TZq8vnrY&list=PLoH7Sjb8-XEikVEAfJ4pESe4NctjnroRj&index=6