Hi there --
Go Button should recover from an audio route change, such as unplugging headphones. Could you send us a "Contact Support" message from the sidebar of Go Button when you get a moment? That way we can see more details about your iOS and app versions and device.
I would also be curious to know if closing the show and reopening it works to restore audio playback? I know that is not always practical in a show situation, but it will help us understand what is going on. Also it might be quicker than force-quitting & restarting the app.
As for opening another app that uses audio, it is best practice to not switch to any other apps while a Go Button show is open in Show mode. Many apps play audio, even if it is not obvious, such as Photos or Messages even. iOS treats audio apps as "last in wins". So if you switch to another app that claims the audio output, Go Button cannot do anything to prevent that. Go Button is designed to mix its audio output with other audio apps but we cannot control what the other app will allow. If that app doesn't want Go Button to mix its audio, Go Button cannot prevent that either.
Brent