Version 3.2.8, Feat: Two Weapon Defense has two issues:
It grants a Shield AC bonus. However, this bonus stacks with item "Shield Amulet" (purchased from Malavon). Given the fact that this bonus does NOT stack with spell "Shield", this might be a bug?
In some cases, this bonus still applies even after two weapons are unequipped. This can be reproduced if you are a Kensei/Monk/Ranger with two weapon defense feat.
Version 3.2.8, Feat: Two Weapon Defense has two issues: