More info here : https://bugs.webkit.org/show_bug.cgi?id=203293

So as everybody here I have the same problem, my test setup is on iOS 13.6.1. It is very bad! I am a WebAudio expert so here is what I found. When our music app is set in background mode (user switches to another app or screen turned off), all the WebAudio AudioContexts inside the WkWebView freeze after exactly 27 seconds. At that moment, our app turns silent and the AudioContext.currentTime stops incrementing despite that the AudioContext.state is still "running". That's the only way to detect that broken WebAudio state I found. And the worst part is that bringing back the app to the foreground don't resuscitate the frozen AudioContexts, they are dead forever, I tried. You can recreate new AudioContexts though but in our case we simply restart all the app, which means the user lost his progress. This is a quick fix waiting for the real iOS fix. It is obviously a big bug introduced in iOS 13. Also I can see that this issue is almost one year old and it has not been fixed, that's not respectful for all HTML5 developer here, that's sad! Hoping someone competent will take this issue seriously. Thanks!

Same problem!! I can see that thread is one year old and still no fix, is this a joke?? I am developping a popular music production app and we run webaudio under the hood. The only way to make the audio come back is to kill and restart the app, ridiculous... I am very disappointed, this is not professional from Apple, they should address this issue and give more info.