I noticed that via the iPhone app/mobile.united.com, flights are showing up with seats in First and Economy as being available. However when I call the 1K desk, they say the flights are sold out. I had this happen to me a few weeks ago as well (1K desk says flight is sold out, but iPhone app showed available seats) but I decided to head to the airport anyways and the lobby agent was able to get me seats. Both instances, it is for a UA reservation on UA metal. Anyone else experienced this type of discrepancy?