Facebook has problems with fraudulent or confusing advertisements. for example, iPad's being advertised for $2, but the user clicking the ad is sent to a penny auction site that bills you $100 when you sign up.... so that domain ends up getting banned, but those advertisers/spammers either create a new domain or they use a redirecting domain that redirects to a non fraudulent domain when they see an Facebook IP (in theory, the Facebook IP would mean it's an intern or Facebook bot checking the URL).
Here's an example of the penny auction crap http://www.fastcompany.com/1771099/facebook-spam-ads-damage-...
and an example of manipulating the landing page URL with a redirect http://www.larrylim.net/seo-online-marketing/facebook-ads-pr...
so maybe it's Facebook's engineers trying to verify the ads are going to the place they're intended to go, but they are obviously incorrectly counting them as billable clicks