Mine showed correctly last August/September, then broke for me in December, and haven't worked since. Really frustrating, as other airlines I've flown have worked fine (B6, VX, etc.). I've double checked all my location services preferences as well, and it doesn't seem to have changed anything. I think it's a problem on the United end, perhaps not geocoding the airport location into the boarding pass? I don't know much about how these things work though.