If you didn’t factory reset the Sonos you sold you may keep seeing problems.

I don’t know the best solution so wait for other folks to comment! (see the 2nd link)

You could possibly Factory Reset all your Sonos, erasing all settings, lists and accounts.

Delete and reinstall all controllers. (clearing data there too)

Power up one Sonos and install it as a new system.

I’d use a new e-mail to insure a clean break.

Get your lists and accounts configured.

Then add your other Sonos to the new system you just created.

FAQ

https://support.sonos.com/en-us/article/reset-your-sonos-product

https://support.sonos.com/en-us/article/transfer-your-sonos-system-to-a-new-account

I agree. Look back in here and this issue has been around for years.

The general responses are along the lines of try drawing a pentagram on the floor, stand in the middle and throw salt over your left should while holding your breath.

Telling customers (YES remember that is what we are) that THEY should resolve the issue by getting a new email and restarting EVERYTHING they took years to setup is really, really, REALLY poor.

The real trouble is that SONOS has gotten very very lazy of late.

They are only interested in us before they sell to us and after they dont give a stuff.

Just look at the whole S1 to S2 debacle.

The CUSTOMER CENTRIC response to this problem would have been to get a dev to write a small bit of code to allow, by the click of a button, the removal of the device.

The argument that this would not be possible is nonsense. Currently if the offending devices are added to another system then they disappear. So Sonos COULD (if they wanted) just simply have the button add the devices to a dummy system which they then purge. Not rocket science or difficult. Better still they could have an archive flag and have the devices still attached to your account but not show as active.

The fact that, literally, YEARS after the problem first appeared in these forum it still isnt solved definiately shows that their priorities are NOT on customer service and customer retention.

With all the things happening around the World these days, I just let these type of things pass me by, who cares‍♂️? 

It certainly does not cause any issues with the Sonos system and how things work. I have a good many old devices including CR100s/200s/Bridges/Dock/Old Play:1s etc. There are far more important things to worry about than losing sleep over trivia, like this. I just don’t let my own OCD get the better of me over such a minor matter, which I choose to personally view as a history of Sonos devices purchased, past and present.