I gave that a try (Copy to Play Order) after I changed a column sort order of the playlist. Updated the XML and then imported to NAS. Then logged back into Plex. The sort order remained the same as it was before. I had changed from a random looking list of songs in the iTunes playlist to being in alpha order for Artists. But it stayed random. I also tried rescanning the library. Neither worked.
In another item, I noticed that some Beatles albums that I have mono and stereo versions of have lost their split. Meaning that for some reason, Plex put the mono and stereo into the same album. So I split those out and now I had two versions as I should have. I would just select the mono ones for example, and then edit it to say "Revolver (mono)" and it would make a new album so to speak and leave the stereo tracks in place for "Revolver". I had to go back and redo about 6 albums or so.
Just to test this metadata issue, after I redid those, I refreshed the metadata and it went back to combining them. I checked the Windows files for the album which I can view under Network / DS720 and the right album name is on each song within the album, meaning there's "Revolver" and "Revolver (mono)" on the respective tracks but in two different folders so I have no clue as to why it's pulling in the data for both of those. VERY strange. These are the actual albums, not the playlists.
Interestingly, I do have playlists for those each and I just checked and they're separated there.
Plex is extremely challenging. It's not user-friendly at all. This is why I'm worried about doing a library metadata refresh because I fear it will change things there just as it did on the Beatles albums as a test case. I had modified those last week so it was fresh in my head so for some reason I decided I'd go check and sure enough, it didn't save the changes.
To check further, I made the change back again on one of the several Beatles albums and then scanned the library instead of updating metadata inside the Beatles, and it did not change it back. So it appears nearly for certain, that I'm going to have to not do any metadata updating.
I changed/tested various Agents inside Plex and other things to try and nothing worked. Oddly, some of the changes I made stayed on a couple of Beatles albums (keeping stereo and mono separated).
There are several confusing elements. For example, when you set up your library you can choose a scanner and agent. Scanner choices are "Plex Music or Plex Music scanner." I have used Plex Music as it's recommended because it's newer. And for Agent, choices are Plex Music, Personal Media Artists or Last.FM. In testing, it seemed to work best for Plex Music to be the choice.
What is so amazingly confusing is under Agents in Settings, you have other choices and order to choose. They have Movies, Shows, Artists, Albums, and Photos. For Artists for example, they offer two sub-groups: Personal Media Artists and Last.Fm. Then underneath are choices of Local Media Assets (artist) and Personal Media Artists. You'd think Personal Media would be "my music" but they advice using Local Media if you have good ID3 tagging but only if you have it very well organized.
So I tried some things but nothing kept the mono and stereo albums as separate albums. That leads me to believe I have some settings not right and/or that maybe some ID3 tagging isn't right. Thought, as I said, the album title is correct on each in Windows on the song files so something is amiss.
So anyway, frustrating but at least I have playlists and that alone is a godsend.
If you have any thoughts, I'd love to hear them. THANKS!