The database table metadata_item_views stores the view history. When you use the dashboard or the dash app to display the play history for a movie, tv show, episode etc… plex will query this table and display that information to the admin.
A design flaw of this table is that its storing various metadata fields specific to each entry, like grandparent_title, parent_index, parent_title, index and title. These fields are duplication of fields already stored in metadata_items. These metadata items can also change overtime.
Take the following example:
- You watch an episode on the day it actually airs. The correct metadata title for that show does not yet exist so it gets a generic TBC or something like episode 1.
- Once watched a watch history row is then created in
metadata_item_viewswhich contains the metadata available at that point. - Then, in 24/48 hours the plex metadata cache catches up and the
metadata_itemstable is updated with the correct information. However,metadata_item_viewsNEVER gets updated so it now contains the wrong old metadata in the history.
A better solution would be to always reference the metadata from metadata_items and never store it in metadata_item_views. The table metadata_item_views contains guid so it should be possible to accomplish this although I’m sure the apps would also need an update.
BTW… I cannot vote on this suggestion due to the absurd 5 vote rule plex have!!! 
