I have a Sonos Play 5 and connected a button to the Sonos Control app. I choose the Play/Pause action and it will start to play but the pause will never happen. If I pause the Sonos on the physical speaker itself, the next button press will un-pause but pressing again does nothing.
Ok, just avoided ST altogether and used an Amazon Dash button and a variation of my python script to control sonos through SoCo upon dash button press.
Works like a charm and even if internet connection happen to be broken.