Any way to get rid of that bugger?
-Tipsy
This probably isn't the cleanest solution, but it seems to have worked for me.
When I first started Paragon Chat at release, I had a legacy chat.txt file. It was filled with whatever leftover channels I had back when Beta was a thing. So, I had old supergroup channels, a Beta Testers channel and weirdly enough a Winter 2009 channel.
Like in your case, it was supremely annoying because no matter what I tried these things would just be laying there, reapplying themselves and just RUINING EVERYTHING. I tried editing the chat.txt file manually but that would invalidate the file - it would no longer load. I tried deleting it but it would just remake itself.
What I ended up doing was unjoining the channels (again!) but joining the ones I wanted too, saving the file (/chatsave) - then double checking to make sure that the changes saved right. The chat.txt file is right there next to your cityofheroes.exe. If everything is kosher then you make it read only. Right click > properties > check the read only box.
Now comes the tedious part. You need to log in to every character and load this file. It may take several /chatload iterations to get on and off every channel. I think this mostly depends on how many new channels you've joined.
This is what worked for me.