This seems like a pretty rare bug but annoying anyway. On my system I found that when logrotate would run, some log files such as /var/log/maillog did not rotate properly.
Write to <tag>maillog</tag>
Daily, move maillog to maillog.1
Daily, move maillog.1 to maillog.2
However it was going
Write to maillog,
Daily, move maillog to maillog.1, keep writing to maillog.1
Daily, move maillog.1 to maillog.2, keep writing to maillog.2
According to this bug tracker entry and this post, it is a problem with the version of logrotate, and people having the /tmp directory on a separate mount (I did not even have mine set to noexec like I should have, and I still had this problem [fixed now, by the way]).
It is easily fixed by installing the version of logrotate from the