I hope you submitted a system diagnostic, and called Sonos Support to discuss it, so they have a case they can forward on to the coders. 

Are you saying a System Diagnostics would detect what the WEB Player is doing?

I certainly don’t know for certain what is included in a diagnostic, but have always assumed there is some aspect, as the speakers need to be aware of what is being sent, and why. 

With all of the previous teams I’ve worked with, hard evidence / reproducible cases beat out anecdotal complaints, every time. QA teams didn’t often report an anecdotal bug, it required reproduction steps. 

Bruce:

 Thanks.  Since it’s only the somewhat weak WEB app that doesn’t see the Room I’ll let it slide for now.  Maybe in the future the WEB app will be more useful.

Thank you for using all those apps (including two of mine!).

None of the apps you listed use the Sonos Cloud API, which is why they work fine. As users of the new mobile apps will attest to, the Cloud API is simply not reliable yet.

One thing to check is firmware versions: the “missing” speaker might be out-of-date w.r.t the others, and the Cloud API is super-fussy about that. (This is also the cause of device volume controls sometimes missing in the mobile apps). I don’t understand the fussiness, the API doesn’t change that much.