I have a zimbra single server installation and all its ok with email, filtering, antispam, antivirus, etc..
System filter thousands spam per day, but charts always show "0" filtered.
All charts are shown, but SA/AV charts always show 0 mails filtered, but SA/AV is filtered on incoming emails without problem.
Really all its OK, only SA/AV chart data its incorrect.
I revised logger and zmstats, but all appear to be ok.