I started an Apple One Family Share. All my previous individual subscriptions updated the status to Apple One, as the provider. When I invited a family member and they accepted, all their subscriptions updated, too, except the Apple Music. They had their own individual subscription with an expiration date. After that expiration date passed they were still excluded from that particular Family Share subscription. Can't figure out how that should be shared and accepted. There is a disconnect somewhere precluding Apple Music Sharing using Apple One for this individual. Where to look?
Both iPhone have 16 and using iOS 27.0.1.