Music app—shuffle doesn't group multi-movement works together

In iTunes, all the tracks making up an individual work shuffle together, i.e. when you select a playlist and hit the shuffle button, it will treat each "work" as though it were a single "song" for shuffle purposes. See screenshots—here's another one from right now; this is a playlist on shuffle. I haven't added any songs or changed the order in Up Next, this is just what happens when you hit the shuffle button. I am on iTunes 12.8.0, if that makes a difference (it's possible that this functionality has been changed in newer versions of iTunes? But this is how it's worked since 12.5 when Works and Movements were first introduced)

This behaviour doesn't appear in iOS and from a search of third party apps, I'm increasingly uncertain whether that's a Music app limitation, or whether those fields (Work and Movement) simply don't work the same way in the iOS API.

The behaviour is the same regardless of where I'm playing from—songs list, albums, composers, genres etc. Shuffle treats all tracks as though they were individual "songs" instead of shuffling the "works" and preserving the order of the movements.

update: I updated iOS to the latest version, removed all music from my iPhone and redownloaded it. Shuffle continues to split up individual "works" rather than grouping them together.

Have also observed that this does not happen when playing the music from my iPhone through iTunes on my computer—it's the Music app on the phone itself that is the problem.

I would appreciate any advice or other solutions.

It's unclear why it works that way when iTunes doesn't—and somewhat concerning, since iTunes is about to be replaced by a ported-over version of Music.app which presumably works the same way it does on iOS.

Essentially this makes the work and movement tags useless apart from cosmetic purposes.