Content - Loot suffix / prefix miscalc's
Priority - Low
I PrntScr'd this, but somehow the cache cleared.
Normal vanilla leather armour - 12 AC / 5% slashing
Green Fortifying Leather armour of Earth Resistance - 10 AC / 5% slashing
Thus, at least on armours, you get a worse base AC and resistances don't seem to being added; not such a happy feeling after maiming the
[EDIT]
Found a random vanilla leather armour drop with 3 AC, 100% durability. I'd say leather armour is just plain bugged atm.