Room missing from S2 app on iPhone but available on iPad

I have two Sonos 5 speakers (gen2) paired in my living room.  When I connected them, the app said I have a very strong wifi signal.  Sometimes when I look for them on my iPhone (S2 controller), all other rooms are available but the living room just doesn’t exist.  I will then look at my iPad (sitting directly next to my iPhone) and my living room is there and available.

Later on, the living room will just “reappear” on my iPhone.  Also, those speakers are up on a high shelf so it is very inconvenient to unplug and reconnect them as a solution.