My bad - I uploaded a new log yesterday morninng which (hopefully) shoud only have trying to add the playlist “Unplayed: Added in the last day” which has around 7k items at the time of adding.
Interestingly, Symfonium popped up a notification saying it couldn’t import duplicate playlists, so I renamed the existing playlist in Symfonium, and tried again but got the same issue.
I get the same error with the playlist “Label Unplayed: 1, Voidhanger” - which is odd, as that playlist doesn’t appear in my Symfonium playlists page.
From the logs the playlists exists, but the duplicate check is made on the Plex IDs so they can be named differently in Symfonium if you renamed the playlist at some point, or you have a filter.
I’ll add the actual duplicate name in the logs in next release to help find this.