Apple Music wont play synced library songs, pop-up says "device was previously used with a different ID"

Hello

I just started using my partner's iPhone 13 pro max. I signed out of iCloud etc. on the phone and reset it as per the phone's process in Settings.

I restored the iPhone using my own backup and everything appeared to be perfect.

I have an Apple ID for iCloud and a different ID for iTunes/Music and purchases. I checked the phone had registered the right ID's and they are correct.

In fact, the Music app had already recognised all my playlists and my library was already synced up as expected.

The problem occurs when I try to play a song that is in my library but that is not in Apple Music. Every time I click on one of these songs, I get the following pop-up –

"Allow this device to use Apple Music?

This device was previously used with a different Apple ID. To access your subscription, you will need to sync your library with this Apple ID. You will not be able to change to a different Apple ID for 90 days."

There is then the option to either Cancel or Transfer but if I click Transfer nothing happens.

I've seen mentioned in my search for this problem that a device could be still somehow connected to a device so I checked my partner's Apple ID to see which devices are still linked to that ID but this iPhone is not in the device list.

I've also seen that there are certain circumstances where a device must wait 90 days to be associated with another ID but this has never happened before (my last iPhone 8 was also inherited from my partner and using the same process I reset it and restored from a backup of mine and had no problems with Music. Also people have mentioned the 90 day 'counter' going down each day but the pop-up I get still says 90 days after almost two days.

I've double-checked that Music is using the right iTunes ID and also signed out and signed back in again. I also tried switching off Sync Library, then rebooting the phone and switching Sync back on but nothing changed, still the same pop-up comes up.

The phone is running iOS 15.5, so up to date.

If anyone has any suggestions, I'd be really grateful.

Thanks