nginx – Feature-Policy fullscreen not working as expected


I have NGINX running as a reverse proxy and set the Feature-Policy header with fullscreen to “self”. The site itself contains the HTML5 video player, but unless I set fullscreen to “*” the fullscreen button on the video player is disabled. What could cause it to be disabled when set to “self” (or origin for that matter)?

Here’s the Feature-Policy (so far, because I noticed there are still a few more I could add):

    add_header Feature-Policy "
    accelerometer none;
    ambient-light-sensor none;
    autoplay self;
    camera none;
    document-write none;
    encrypted-media self;
    fullscreen self;
    geolocation none;
    gyroscope none;
    layout-animations self;
    lazyload self;
    legacy-image-formats self;
    magnetometer none;
    microphone none;
    midi none;
    notifications none;
    oversized-images self;
    payment none;
    picture-in-picture self;
    push none; 
    speaker self;
    sync-script none;
    sync-xhr none;
    unoptimized-images self;
    unsized-media self;
    usb none;
    vertical-scroll self;
    vibrate none; 
    vr none;";

And here’s an example of a video player:

<video playsinline controls autoplay preload="auto">
    <source src="https://serverfault.com/stream/364a42a508d89886d277f779dafb51b7" type="video/mp4">
</video>

There’s no added JavaScript or anything.