OK, this is weird.
A user with is receiving notices for a board she has not visited in years. However, when I check the Subscriptions in the Joomla Database, her User ID does not have any subscriptions for that category - and they are new posts that she has not subscribed to.
The Email notes she is subscribed to the category (not the topic), even though in the Kunena DB she is listed as not being subscribed (Subscribed=0).
I'm not sure now if this is a CB / GJ issue, or a Kunena issue... my only hunch is that it began right after installing GJ 3.0, and JV-ShrinkTheWeb (which shouldn't interact with the forums).
If you need access to my site, I can arrange for a Guest Admin login.