Apple Music App (Golden Gate MacOS, Mac Studio) won't play parts of a 20 year, 10,000 song library.

Brand New Mac (Mac Studio, M5 Max), and in general it works very well. Of course, it's running the most recent version of Golden Gate MacOS (27.0.1)

But inexplicably, about half our Music library won't play. The same songs play flawlessly on my iPhone.

I've looked for a pattern without success.

The bug affects some songs ripped from CD, but not others.

Some purchased from the iTunes store play, but not others.

Some songs purchased 15 years ago play, others from the same day long ago don't. Same with songs purchased in the last year.

Some songs that are part of the same album play, others don't.

Just Baffling.