Silly me… I followed Will’s (excellent!) instructions to enable Snapshot Replication, and very ‘smartly’ thought I’d add my Plex-created ‘Music’ folder.
Snapshot Replication created a snapshots folder in /volume1/music/#snapshot. The folder currently contains 12 snapshots. When I open the Music folder in Plex, it shows each album - you guessed it! - 12 times, as Plex ‘sees’ each snapshot’s contents as the artists and their albums and consolidates them when you use Plex Music.
I’ve now disabled Snapshot Replication on Plex Music and waiting for each "Immutable snapshot” to end its protection period so I can delete it.
I’ll go back to using Hyper Backup on my Plex Music folder!
Note: I only used Snapshot Replication on the Plex Music folder but presume using it on other Plex folders would have caused the same duplications problem.
Question: does anyone know if the Plex Music library folder can be moved to a user in ‘homes’ or, is it locked to be /volume1/music?