re: 1 - For user shared links, Facebook redirects to anonymize the referring profile. I suspect they forgot to do the same for ads, and it was an honest if frustrating mistake.
They didn't use to do this, the only reason they redirect now is so that if a link is deemed a virus of some sort they can easily stop it from spreading, and you can enable a setting so that before visiting every link you get an interstitial that tells you that you are leaving Facebook.
