I'm on the opposite end of this problem, every invite I receive is being auto-declined. We get added to friends, I don't ever see the invite, and I can't queue for their premade again.
Have gone through and checked all my add-ons - I don't have anything that messes with auto decline/accept of invites. In fact I haven't changed any add-ons or options at all since I last used OQ successfully. :(
Just tried a fresh reinstall of OQ and will update if that works.
Edit: Just did a fresh reinstall and no idea.. I've had 3 groups able to invite me, but at least 2 unable to still. Not exactly sure what's happening here.