Version:            (using KDE KDE 3.5.5)
Installed from:    SuSE RPMs
OS:                Linux

I was checking on my filter rules and editing them. Now, when I do not shut down KMail before I shut down the system, my POP filter rules all get lost. This happens every time and not sporadically. 
When I shut down KMail after editing regular filter rules, the POP filter rules will remain intact.
I do not know how the two (POP filter rules and other filter rules) do interact, but somehow this doesn't seem to work properly. Note that I do not need to edit any POP filter rule in order to have this happen. It just happens when I edited the regular filter rules and forgot to shut down KMail by itself.
I must add that I always want to leave KMail open with a few other apps, and that I want to shut down my PC daily for ecological/economical reasons. Otherwise, this wouldn't be a problem. KMail restarts fine when restarting the system, but has forgotten the POP filters.
OK, I think I explained it enough...
BTW. I use OpenSuse 10.2, the regular package, no special downloads.