Workaround SpamAssassin Y2K10 Bug (Mac OS X Server)
Well a little patience and it showed up on one of my mailing lists (and now on Apple's KBase: TS3187):
Either:
1) Add to /etc/mail/spamassassin.conf
score FH_DATE_PAST_20XX 0.0
or
2) Fix the rule in /usr/share/spamassassin/72_active.cf by replacing the FH_DATE_PAST_20XX line with:
header FH_DATE_PAST_20XX Date =~ /20[2-9][0-9]/ [if-unset: 2006]
or
3) Run sa-update and that will fix it as well. (Thanks to Matthew Bryant)
sudo sa-update --nogpg --updatedir /etc/mail/spamassassin --debug