I have similar issues with my Play:3s dropping out that have been discussed numerous times here. I only have two Play:3s and put these in a tight location above the kitchen cabinets (play:1s wont fit). I've read countless trails on network interference, IP addresses, memory issues, and so on.….
I have a significantly large sonos array upstairs (18 individual components in various rooms) and regularly link all these together. My Play:3s predictably drop in and out of the music stream.
I would usually start streaming music through the living room TV (arc ultra + Sub + Era 300 surrounds), then add additional rooms/components to join that living room group. This is when I hear the Play:3s dropping in and out.
Today I started streaming straight into the kitchen (Play:3s). By themselves with no other components in the group there is no skipping or dropping in and out as seen before when starting in the living room. I then added the new living room TV components and things fell apart with skipping & dropping. I could even see where the app was struggling to add the living room to the group. In fact it took two or three times to apply the added components. Many times it would not and even on one occasion the app just quit. Had to restart my phone & app to recover.
Ive repeated this with all the other rooms and components and my system runs great - until Play:3s are introduced and the connection quality deteriorates. Lastly, I moved the Play:3s to completely different locations with the same results.
Bottom line this ‘may’ be network interference, but Im convinced this is a serious backwards compatibility issue. Sadly, its time to ditch those play:3s.