Quote:

Youtube will assume any browser useragents not on its (small) list are always desktop ones. In that case it'll throw you straight to m.youtube.com/?app=desktop. Extremely irritating behaviour, because the site should give you what you asked for, not what it thinks you asked for.

If you can spoof useragent, try something like iPhone or Android.

This is not really a solution ecause you'll get redirected to mobile sites all over the internet when using OWB and that's definitely not a good thing. But if does work it might give you an idea of what's going wrong.