1. I know the labels are gone becuase I use color labels extensively in my workflow. I assgn red with an import preset to all photos to indicate that they havne't been edite, and after editing i assign green to indicate a photo is "finished." All Green photos automatically go into a set of smart published collections, which i then publish to a hard drive on another PC that is constantly chrome casting a slideshow to all my photos to a TV. So, virtually all of my photos have a color label.
2. If i use the filter bar to find all "green" photos it says there are none. And of all the smart collections that automatically contain all of the "green" photos are empty.
3. I opened a number of back up catalogs going back a few months and LrC is not showing ANY of my color labels.
4. I am 1,000,000% certain that the color labels were assigned when those backups were made. Please note that virtually ALL of my photos have a color label, so the first thing I noticed when i opened LrC today is that all of my labels were gone. I wouldn've noticed it immediately whenever i open LrC.
5. Attached is a screen shot showing the grid view. You'll see that only one photo is green (I just made it green so you could see that it shows green when green is assigned).
I wasable re-assign the green labels without too much pain becuase i happen to have a static collection that I put all green photos into to sync to LrM.
I am totally baffled and pretty concerned that this happened. Equally concerning and amazing to me is that when i open my prior backups ALL color labels are gone. There is NO DOUBT that the photos in those catalogs had color labels. It appears that LrC just forgot how to recognize color labels (but when i assign them now they work, so this is weird).
It's really disturbing that not only did my color labels disappear, but they are not recognized in prior backups. This is the most disturbing part.
This is a serious bug. I don't know how to submit a bug to Adobe, but if someone tells me how to do it I will