Pretty sure the issue is the same as:
viewtopic.php?f=43&t=31128What seems to be happening is that the spammers have hit some groups with random "From" field spam which is basically DOSing the group to Newsbin.
I spent the day today coding a work around. It'll be in B3. Might give you early access to B3 so, you can test it. I'll talk to Dex about it.