Description of problem:
Yum wanted to update the i386 glibc and mozilla packages this morning
despite the fact that the x86_64 versions were not available.
From my understanding, you want to maintain the same versions of your
32 and 64 bit libs but yum isn't doing this.
Yup, that's the way rpm currently returns archScore(), i386 is
compatible with x86_64.
The underlying problem is transient, the upstream repo
was not yet finished syncing. That's real hard to detect in software ;-)