Have you called Sonos Support to discuss it?

It sounds like there’s so:etching odd going on, I’d certainly be tempted to try a reboot of the device, by powering it off completely, then powering it back up. If that failed, I’d consider a factory reset , but only if I had other Sonos devices to copy things back to it. And, failing that, I’d reset it by pulling the battery out for two minutes. 

But my first step would still be the phone call. Those other things are fairly intrusive. 

Thanks Bruce,

Sounds like good advice. I'll give them a call. I figured if it's happened to me, it's happened to someone else.

I don’t recall it having being posted about before, but that’s certainly no guarantee. My memory is equally faulty as the next person, and perhaps more so. 
 

It certainly doesn’t appear to be a common issue, for whatever that’s worth (nothing!).

I did not have time to contact Sonos today but the speaker fixed itself after turning it off and on about six times. All good.

Heh. While I’m delighted it’s working now, that issue would bug the heck out of me. If it happens again, I’d definitely submit a system diagnostic within 10 minutes of it occurring, then call Sonos Support when you can. 

Sure thing, I'll keep an eye out. Hopefully it's a one time glitch.