Mismatch_cnt is not Zero

After having repotted a Fedora Core 12 installation I was challenged with the apparently quite well-known warning message /etc/cron.weekly/99-raid-check: WARNING: mismatch_cnt is not 0 on /dev/md0 which came from Anacron into my inbox (The subject line starts with Anacron job ‘cron.weekly’). I remembered that I solved this problem on that Fedora server before,