This seems to be a long time problem in Plex. see this post Problems with tracks in a Various Artists album matching to the artist
I encountered this issue while building a Plex server on CentOS 8. My current libraty is on Windows 10. I found that Plex on Windows reads the Various Artists albums correctly. Artists are showing up in the All-Artists-By Title. I have 1698 artist on Windows and 750 in CentOS. I have been looking at this for weeks thinking it was permissions, or something in the file system. I then last night had this idea to check the number of tracks… I know why not check this sooner. … Who knows. The tracks are the same in both. When I swith to All - Tracks, I get 27115 in both Windows and CentOS. The tags on the files are accurate. Seems that in Linux or at least CentOS, Plex handles the songs differently. So far the other Libraries do not have this issue. I really wanted to go with Linux to ensure Plex would startup after a reboot, and to reboot less. This was very disappointing.
