I have never seen such issue in the past, are you sure that you have opened the correct catalog?
Yes, I only have one catalog -- always have.
What happens if you save the current catalog and open the most current backup of the catalog instead?
My recent backups were the same, but I found one from several months ago with the facial tags. So I don't know how the tags dropped out of the catalog but they did. Now I just have to figure out how to merge the catalogs without messing something up ....