Amazing... Your banner works fine. I have scrapped the banner I was using and gone with exactly what's in our /etc/issue file, and it works too. I can't say what the issue was, but I've got to deliver a couple of these systems today so we'll go with what works.
On a side note, I did find that since the default umask is 027, when Puppet runs dconf update, the /etc/dconf/db/gdm file has 640 permissions and the gdm user can not read it, so settings were not being applied as desired when puppet makes changes. So that confused the issue even more. I'm not sure how I'll resolve that yet, but for these first couple of systems I will manually set the mode on that file. Thanks for your help!
