I have built a PWA that calls the javascript API navigator.geolocation.getCurrentPosition which prompts the user for location access when the Safari permission is set to Ask. This is the correct behavior and works as expected when open in Safari.

However when added to the Home Screen and running with a display mode of "standalone", the location alert does not open on my phone (iPhone 13 mini / iOS 15.1.1). And the call never times out. Then if I switch from the PWA to Safari the location alert / prompt is suddenly showing in Safari. So it seems that the alert is targeting the wrong "tab". This does not happen if the PWA display mode is "browser" or "mimimal-ui" with either of those it behaves normally.

I can only replicate this on my phone (iPhone 13 mini / iOS 15.1.1). I have also tested on various older phones (15.1.1 and 14.7) as well as several emulators and they all behave as expected. It is possible this is a obscure setting on my phone but it does feel a lot like an iOS Safari bug.