Template Category names all say "Templates"
 

I'm having the exact same problem as was posted in this old thread.

It seems like its a database issue, but I'm not sure where to begin troubleshooting it. I ran a Repair/Optimize and everything was ok, but the problem was still there.

As was suggested in that old thread, I searched the Languages/Phrases for "group_" and all of the category titles are in there.

We just upgraded to 3.8.3 from 3.6.x, but the problem wasn't there right after the upgrade, it was only recently.