According to my latest flight is is only 500 miles? What's up with this?

Activity Date Description Miles/Points Award Miles Bonus Total Miles Segments
8/16/2012 United 1733ZS
Washington (DCA)-Houston (IAH) ZS / ZS 500 500 1000 1,208 1

Another system integration screw-up from your friends at United. And with three big problems with flights in the last 24 hours, I realize this is minor compared to keeping the planes safe.