I experienced some weirdness when wearing/removing armour, boots etc... (Also as a note: It seems that equipping armour items in weapon hands, such as body armour or boots, still makes the game think you are wearing them).
Here's one example with screenshots:
I was wearing no boots:
Then I equipped some boots, and DV/PV weren't modified at all:
Then upon removing the boots, DV/PV changed as though I'd just put the boots on!
I played around with this for a while, and sometimes equipping the boots didn't change DV/PV as above; and other times it did change them but did so in reverse (as though it was
PV/DV instead of DV/PV).
Also, when equipping some 'studded leather armour [+1, +3]', my DV/PV are modified as if the armour is [-1, -3] instead of its actual value.