Unable to play Apple Music songs on Sonos - Song Not Encoded Properly

I have a very odd bug that Apple have spent a couple of remote support calls trying to sort without success. I wondered if you could help, community.

I have albums in my library bought from iTunes Store in the last couple of years (so not from old DRM times). They appear, as they should, in my Apple Music library, but many of the songs give an encoding error when played on Sonos.

Apple said Sonos hasn't paid for the license to play music this way. Sonos said it should work, sounds like an Apple problem. Both pointing at each other. Do you know the answer?