Armor Damage

I noticed the armor wasn't taking any fall damage.

What I expected to happen was...:
I expected the armor to take some damage.

What actually happened was...:
the armor didn't take damage.

Steps to Reproduce:
In the pic, I have fall damage results alongside creeper results. They all go left to right top 1st then bottom.
1. fall from great height (around 18-21 blocks)
2. see results
3. put armor on
4. repeat steps 1 & 2
5. compare results

Edit: Still happening in 14w26c
Edit2:Still happening in 14w28b &14w29b
Edit3:Still happening in 1.8-pre3
Edit4:Still happening in 1.8