Not sure whether this is a bug or you designed it this way. (95% is a bug)
The description of the perk says “With the offhand free, gain +100% melee defence”.
But it works like this: when the perk is selected, any upgrade in melee def will doulbe. And this additional def wont gone even if u put shield on.
Then u can have a super high def person.
Notice: any def points added before the perk is active wont count.
This makes the perk super OP, and one should get this perk as soon as possible in current version.
Hope can be fixed.
Edited: So sorry, I get this all wrong, the perk works well, pls ignore this/delete this