I have the same problem... No fresh idea to help me ?
I have not change my reverseDNS, seems not to be a good idea at all... ?!
I've haded my domain in /etc/amavis/conf.d/20-debian_defaults too...
I don't receive the logwatch emails, it's not practical.
Recently, on one of my two servers encounter the problem, the mail arrived, but that this day there...
Probably a ghooost
Falko, an idea ?