Can you check with Chad as to why the forum seems to be getting more bot posts than before the upgrade? Surely the point about the upgrade was to plug security holes?
It could actually be some idiot actually going around registering and posting it. Rick may be able to confirm via the IP.
Rick, In one of the releases UBB allows you to switch on a "confirm" step in the registration where by when someone (or a bot) joins, they have to respond by clicking a URL in an email sent to the registering email address before they can post. Might be worth doing this. I am not sure which release it is, but I'm sure it must be in 3.6.n !