Firefox 65 on Android 7. I add a PWA to the Home Screen in FF. If I click on the FF HS Icon when FF is closed, all I get is a blank screen (PWA does not work). However, if I have FF open before I click the FF HS Icon, the PWA works. This is not the behavior observed using Chrome. The Chrome HS Icon works regardless of whether Chrome is running. I have tried this with several different PWAs and the result is the same. I don't understand why this is happening in FF...