Strange. I'll see if I can get a DM to debug me or something.
I got a DM to try and help me. The debug wand removed the Shield AC bonus from Parry but whenever I drew a weapon, the bonus would not go away once I unequiped it. We tried relogging, killing and resurrecting the character, re-taking her previous level, but nothing seemed to work - when I unequiped her weapon I'd get the removal message but the AC would remain. We also checked if it was simply a display bug by attacking the character, but the AC shown on her character sheet was accurate. I checked my other character with parry and it was working fine for her.
The bugged characters name is Sofiya Tatsuo. Seems she is the only one bugged, everyone else I speak to has it working flawlessly. I'm hoping the bug will disappear as mysteriously as it came next server reset.
Still, free AC when unarmed. There are worse bugs.
EDIT: lol, I just found the cause. If I equip/unequip one single weapon it adds/removes normally. However, if I use my dual-wielding equip/unequip quickslot, it does not remove correctly. So there you have it.