Ok, so guess what? Apparently, when I purged the cache, it was not Bridge's cache. When I opened Bridge to check the star ratings, I got a warning from Bridge about the cache. I was confused because I knew I had clicked on a "purge cache" button somewhere. Well, I went into Bridges preferences and clicked another "purge cache" button and it took awhile. After that, all of my labels were back. Sorry to have wasted your awesome brain power over this. I really thought I had emptied the cache.