Incorrect armor/deffensive stats showing in the menu

Hello

is there a cryptic way of counting stats showing in the character stat menu or it’s a bug ? 
I have helmet that shows 59 armor and chest that shows 98 armor

but in character stat summary it shows I have 20 defense/armor in total 

does item not count at all there, and that shows only some passive buffs or what is the point of stat summary ?