Kirk McElhearn, writing for Kirkville, added the album Ultimate Sinatra to his Apple Music Library. He writes:

When I started listening to it, I noticed that I wasn’t hearing all the songs that I knew. I looked at this album in iTunes, and I was surprised to see how it displays.

This is a single album, yet iTunes shows it as a number of different albums with different titles. I’ve sorted by album so each title should be grouped, but you can see there are four different titles for tracks in the first grouping. And that first group of tracks, which is hanging together as an album, has track numbers in a seemingly random order.

This is typical behavior for Apple Music when it comes to a greatest hits or collection album. Apple saves space by storing a single copy of a track in the cloud, then points all references to the same song to that stored version, even if it is not the exact same copy.

But Kirk’s problems go deeper than this. Read his post for details. What a mess.