Having "sharedscripts" in a logrotate config section means that the postrotate
script is NOT called before the files are compressed.  This leads to lost log
entries; if you have a couple of large log files every day, for example maillog
and secure, entries logged to maillog between the time it is compressed and the
time secure is compressed are lost.

This is the documented behavior of logrotate.  Either logrotate needs to be
changed or "sharedscripts" should be removed from the standard logrotate config
files.