If it were a bug, this thread would be 100 pages.  More likely your phone had a duplicate IP address and switching wifi off and on cleared it up.

Clears it up temporarily. My son's iPhone has no issues. This just started happening with the last update 

As I said, duplicate IP.  Until you do a full network refresh, the router's going to keep handing them out.  You need to reboot your router, then reboot each Sonos.  If you wish to fix it permanently, reserve IP addresses for your Sonos units in your router setup.

Why no problem with the iPhone on the same system? 

I use both iOS and Android tablet Sonos controllers and am not currently seeing an issue with the latest Sonos App. Admittedly, it sounded to me like there is something on your android phone blocking the SSDP multicast ‘discovery’ of your Sonos devices on the local network. Do you perhaps have any security software running on the phone, such as a VPN service, firewall or antivirus etc?

Any MAC address ‘spoofing’ features running within the network connection properties, such as those  similar to ‘Private WiFi Address’ (albeit that is usually enabled by default on Apple iOS mobiles)? 

Hope the above information helps you to resolve the matter. If the problems persist then it maybe best to speak to Sonos Support Staff, together with a diagnostic report, to see if they can perhaps  assist you to resolve the local ‘device discovery’ issue.