I use an application I love called Hazel on my Mac. It watches files and folders for almost anything you want and then applies rules to them that you set up.

One thing I use the most is rules that react to tags. When I tag files in Downloads, they magically move themselves where they need to be. You can burn through a long list of files, tag them up, and then move on while they sort themselves.

This rules except suddenly the keyboard shortcut I had set up for tagging files and folders stopped working. I seriously couldn't figure out why it wasn't working for a couple of weeks. I switched to right-clicking on files and tagging that way.

This morning I did a little more digging and finally figured out what was wrong with the shortcut. It is kind of maddening.

For my shortcut's menu title, I had "Tags...". I was using three periods. This is incorrect. It needs to be an actual ellipsis, which is made by pressing Option-semicolon.

After that, you might need to relaunch Finder, then tagging with a keyboard shortcut should be back.