That seems odd. An update shouldn’t be able to change or even delete a registration. Have you called Sonos Support directly to discuss it?

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

You can try force closing and re-opening app to see if it then shows correctly after an app refresh.

If not, a simple reboot of the Connect:Amp can be another simple solution when a product shows as ‘not registered’.

Thanks guys , I was holding off calling Sonos support as didn’t want to waste they’re time if was a simple solution 

will try what u have suggested 1st