Under the Music and Video scope the is a section showing the most popular youtube videos right now. If one clicks one of these you get a larger preview of the video along with a description. Then you can click the preview and the browser opens up and the video starts. This hasn't worked since OTA-8 or OTA-9. Right now if you click one of these popular videos then you just get a white screen. There is a progress bar at the bottom for at few seconds so it seem to be loading something but like I said before you end up with a white screen. So one has to load the browser manually look for the video via different methods. There reason for this could be something has chenged on the youtube side so it doesn't support whatever Ubuntu Touch is trying to load with the preview of the video along with the discription.
The scope simply uses the url dispatcher to pass the url to the webbrowser, so if it works otherwise its hard to explain as there should be no difference. Working on the mx4s here.