Hi.  First I should point out that this has nothing to do with the app disconnecting from a speaker.  The app is not a music player, it’s a remote control.  It is just showing you what is happening, which is that you are ungrouping speakers and then the system appears to be regrouping them.

I have never yet seen (in many years in this Community} a case where the Sonos system spontaneously regrouped speakers.  I have seen several where another application did it, e.g. Apple Homekit.  So my first question is do you have any sort of smart hub that could possibly be causing this behaviour?

I am not saying it can’t be Sonos doing this, just that I will be surprised if it is.

Edit- Alexa groups are another possibility.

Thanks John.  No I’m not running any smart hub stuff. It seems to be ok now - I think its getting confused with 2 or 3 of us having the Sonos app and playing tracks at different times (which any of us should in theory be able to do).  I would say that I literally watched the app group the Move after 30 seconds totally of its own accord, I had to gather up 3 phones in the room just to make sure we were all disconnected from it and it was still doing it.  To be honest there have been several occasions where it will play music and then none of us can turn it off or one of us will have all the devices listed and some will only have 2 or 3 (I have 5). I have had Sonos kit for 15 years -  I dont want to use this post as a moan but it seems that the Sonos system spontaneously grouping speakers is not beyond the realms of possibility given the issues I have experienced recently.