Thanks. I thought it might be something like that. I understand that chattr locks and protects files, but not knowing much more than that, I didn't do it !
I get both...
----ia------- /etc/yum.conf
So, I'll take your advice. Should I chattr this file again when I'm done? I suppose it was done when my NOC did the initial setup on my box, and likely to prevent inadvertent overwriting. It does seem likely though to be the culprit in my initial file lock problems on yum when upcp runs.