I guess this is a know issue/limitation of how plex handles track identification and linkage across albums. It’s also most like quite complicated to resolve which is why you get radio silence from plex on it.
I’ve fought with this since I’ve started moving my mid sized music collection to plex. I suspect (but I cannot be 100% sure) it’s something over at musicbrainz changes which then changes the guid (plex://track/xxxxxx) id which plex uses to identify individual tracks. Once this changes its like rating/playcounts are starting again as its a new track from plex’s perspective.
I’ve seen this happen when doing a plex dance on a album/artist and force refreshing album/artist so I don’t think its limited to just scanning & matching.
Regardless, what I do to try and mitigate this is keep a close eye on my db using a couple of queries:
First: This one select anything from metadata_item_settings (table which stores ratings and view/play counts) and see if the guid is NOT present in metadata_items (think of this table as the master list of items on your plex server).
SELECT * FROM metadata_item_settings WHERE metadata_item_settings.guid NOT IN (SELECT metadata_items.guid from metadata_items);
Anything it finds means something has changed and you can then carefully manually fixed up within metadata_item_settings so they match again. It’s a pain but works …
Second: This one select anything from metadata_item_views (table which dashboard play history) and see if the guid is NOT present in metadata_items.
SELECT * FROM metadata_item_views WHERE metadata_item_views.guid NOT IN (SELECT metadata_items.guid from metadata_items);
Again, anything it finds is again a change and can be carefully manually fixed up within metadata_item_views so they match.
Disclaimer: Use at your own risk here and backup is always your friend.
Will this find standard playlist issues, I’m not 100% sure. I decided to shy away from those playlist due to how limiting they are in plex and just use smart playlist instead. I can control what is in there based on criteria. So far its working well and better than bog standard playlists. Good luck.
