The same kind Attributes do not combine if they are on different items (Armor Slots and Active Slot)

What I expected to happen was that the Attributes (+4;+7;+6;+3) on my armor set would combine and give me a total health boost of 20 Health Points.

What actually happened was that I've got a Health boost only from one of the armor parts that was lteast updated.

Steps to Reproduce:
1. Give your self at least two armor parts with same Attributes, but different values.
2. Put them in your Armor slots.
3. Notice, that you gained health boost of only on oh the Armor parts that was put on the last.

And sorry for my bad English, I'm from Lithuania.