[BlueOnyx:07491] Latest Update destroyed my Sendmail

[bluequartz at ozin.com]

This morning I noticed that SMTP was bouncing to my server.
Restarting sendmail failed
Looking in /etc/mail I found that both sendmail.cf and sendmail.mc were 0 bytes.

Fortunately in /etc/mail were also:
sendmail.cf.bxold
sendmail.mc.bxold
Dates 05:02 the day before (my server is set to YUM update at 05:00 every Saturday)

So renaming them back fixed the issue but it poses two questions:

1. Why did it happen
2. are the bxold copies Ok to run with or was this update meant to edit them in some way?

Thanks

Jason