<snip>
Just in case my previous mail was not clear enough on this:
"Before applying this update, make sure all previously released errata relevant to your system have been applied."
That is what every single Red Hat Security Update says ... and so then the question is, what is "errata".
Errata is ALL UPDATES ... there are Security ERRATA, Bugfix ERRATA, and Enhancement ERRATA.
What this means is ... you SHOULD install all updates, not just Security Updates.