If running 3.2.x version of SpamAssassin... (check with `spamassassin -V`) there is a y2k10 bug in the FH_DATE_PAST_20XX rule, causing all mails getting an extra 3.4 points:
Reference: SA Bugzilla – Bug 6269
The fix mentioned is to update the rules using `sa-update` and restart spamd. The rules in the update directory at /var/lib/spamasassin will get updated.
With the fix applied you should no longer see FH_DATE_PAST_20XX in the logs.
For a manual fix, update /usr/share/spamassassin/72_active.cf and change:
header FH_DATE_PAST_20XX Date =~ /20[1-9][0-9]/ [if-unset: 2006]
to:
header FH_DATE_PAST_20XX Date =~ /20[2-9][0-9]/ [if-unset: 2006]
Related reading on sa-update: SpamAssassin RuleUpdates