lucy24 - 12:12 am on Aug 18, 2013 (gmt 0)
and yet there's a preview snippet of it right there
Was it a brand-new preview as confirmed by logs? Previews aren't cached very long, but they're not requested fresh every single time.
You know, of course, that Preview isn't done by the googlebot and doesn't include a request for robots.txt. (This applies afaik to all search engines that have a preview feature.)