I have a premium music library. I have re-created it several times, but I continue to have the same problem. That problem is duplicate artists and albums being displayed. I asked this question in the OSX specific forum, several months ago, but have not discovered any solutions to it, so I thought I would broaden the audience a bit.
My original post, and pictures illustrating the problem are here
https://forums.plex.tv/discussion/181545/duplicate-artists-and-albums#latest