I've been having this bug after the last updates went live on Steam. It seems an bump mapping bug at first, but things get weird at some points.
I'm unable to describe this bugs with words (and wasn't lucky to find anyone else suffering from this), so I recorded a video (sorry for the bad quality)
If it matters, I have Dawnguard installed and my FOV is set on 90 (altough changing it doesn't affect the occurrence of this bug)
Thank you
Video link: http : //tinyurl . com / 9c6qb8h
(copy and paste it on your web browser, deleting the spaces between the words. Forum does not allow me to post URLs)