I have a same problem.
/var/log/mail.log
--- CUT ---
Jun 7 21:19:33 s1 spamd[12679]: spamd: processing message <
[email protected]> for admin:1003
Jun 7 21:19:37 s1 spamd[12679]: spamd: identified spam (18.0/5.5) for admin:1003 in 4.3 seconds, 1432 bytes...