Multiplying heads! (Decorations)

Any head will work. I just used the player head for an example.

What I expected to happen was...:
My heads would switch.

What actually happened was...:
My player head turned to a creeper head.

Steps to Reproduce:
1. I quickly switched the heads back and forth.
2. I kept switching them in my armor slot quickly.
3. The player head turned into a creeper head!