When we open a custom scheme URL before the window load event has been fired it seems that GUM prompt is not displayed after this due to Chrome bug. See more details here https://issues.chromium.org/issues/41398687.
The result in Jitsi Meet is the following:
If the user is joining a call for first time and haven't granted A/V permissions and lands on the deeplinking page we try to open the desktop app via redirect to a custom scheme URL. If the user chooses cancel and "Launch in web" we go to the prejoin screen and proceed with the initial GUM. At this point any GUM call won't display the permission prompt due to the browser bug and will go on forever making it impossible for the user to unmute camera or microphone.
