Good suggestion. Swabby does read these forums, but you might also want to post a bug report on the sourceforge project page. I can't test this on my setup, sorry. But the concept is to make the IP that you "force" appear in search queries you send out, thus people will connect back to that address.
Any chance you can monitor your ethernet packets and see what is happening? If people seem to connect back to you via that port, maybe it's something with your shared files not showing up like they used to?