Depends on what your server is installed on but generally for Windows/Mac/Linux just uninstall and reinstall older version . ( But do not delete PMS folder which contains your database or advanced settings file/registry which has your server ID)
Gotcha. Now…the hunt begins for an older version for this brand new Windows server/system I installed last weekend. 
Okay, all. For what it’s worth, I uninstalled the latest version of PMS and found v1.22.1.4228. After reinstalling this and refreshing music library metadata, Mood, Styles, and Genres are getting repopulated.
I forgot to take a lesson from the world of I.T.: NEVER auto-update. Download the updates, store them, and wait a week or two until you’re sure you don’t hear any screaming.
Thanks for the guidance, @BigWheel!
Thank you very much for keeping us in the know.
I am having the same issue as well. Within the last two weeks, any new music I have added to my library only obtains metadata for artist description. It does not obtain metadata for style, popular tracks, mood, or related artists. I use ‘prefer local metadata’ and supply my own years, posters and genre. I can confirm that this is a new issue recently, and my library used to obtain this additional metadata in addition to what I supplied manually via local metadata.
Add genre radios scan dont work, a mess
AFAIK those are also fixed in the same 1.23 version as those use the Mood etc tags to generate the radios.
Thanks god I found this thread, was going insane searching the forums for something similar and also started a thread thinking this could be a last.fm agent issue.
Waiting for the 1.23 version aswell.
Just updated to version 1.23.0.4438 and refreshed metadata for one artist: it seems to have been fixed.
Also updated 1.23.0.4438-5eef0fd80 on docker on Unraid server, and seems to be fixed now.
Thanks god its fixed. Back to work now, refreshing the whole library 
