Duping

I was just taking of my armor when my helmet duped (iron)

It's not a visual bug they are real objects you can move and throw.

What I expected to happen was...:
To get my helmet to my hotbar.

What actually happened was...:
My helmet duped insteed

Steps to Reproduce:
1. Put on iron gear
2. And shift it off
3. and idk what happened but it might dupe if you like klick it in a sertain way.