Exit Fullscreen Button in Safari is not working if content is embeded as iframe

In Safari 12.0.1 (12606.2.104.1.2) on MacOS the exit fullscreen button is not working (tested on interactive video) - but only if content is embeded via iframe.
The missing part in h5p-standalone-frame.min.js in an ugly fix:

if (H5P.isFramed && H5P.externalEmbed === !1) return window.parent.H5P.fullScreen(e, t, n, H5P.$body.get(), i), H5P.isFullscreen = !0, H5P.exitFullScreen = function() { window.parent.H5P.exitFullScreen(); }, void H5P.on(t, "exitFullScreen", function() { H5P.isFullscreen = !1, H5P.exitFullScreen = void 0;                /* Safari Fullscreen Exit Fix */
                window.parent.H5P.exitFullScreen();
 });