No responses on this, but just FYI, I had this feeling that the problem might be related to putting Pegasus in "offline" mode. So, I for the past 4 days I have not put it in offline mode, and the problem has not re-surfaced. So, there appears to be a relationship there.

 Now, if I can only figure out what to do to get the filters working again, once they have stopped. At this point I don't have any ideas for that.

 But, hopefully the relationship between going offline and filters stopping will be helpful to someone.

Spam filter will stop working. This problem has been going on for months. At first, it would happen several times a day. Closing Pegasus and relaunching would usually fix the problem.

 Now, when the problem surfaces, it does not fix itself.

 At one point, I deleted the words4.db3 file, thinking the database was choking and this fixed the problem instantly. Was good for another few weeks. During that time I was meticulous about doing regular "Cleanup" -- set to purge records older than 7 days.

 Problem returned and now even deleting words4.db3 does not correct problem.

Side issue is that other filtering also doesn't work either. Other filtering problems surfaced before spam filter problem.