Unless you're running a completely clean installation of Skyrim and Dawnguard ONLY, don't report 'bugs' like these.
Well, it is a bug. My only mods are texture and weapon mods. Nothing, at all, that would interfere with this action. Either way, the problem is solved as doing it in third person worked fine. It's only first person that's borked.
EDIT: Also, just to make you happy, I just ran Skyrim and Dawnguard, nothing else. Bug is still there.