So this Saturday I'll be flying CO1 from IAH to HNL on a B-fare.

I waitlisted the miles to upgrade several weeks ago, but it hasn't cleared. I figure that they are waiting to release seats until the flight gets closer. I've been watching on CO.COM as the seats dwindle down. (This is according to the Seat Selection tool for the waitlisted segments. The available seats show up as orange, but still unselectable.) For the past few days, there has only been one seat available (3K), and it still shows that way on the website.

However, now that it's within the 48 hr window, the flight is showing up on the PDA site. They are saying First is Full, with 6 people upgraded.

Is this likely because the seat is blocked for some reason? Crew rest or a broken seat perhaps? The PDA site is saying the F capacity is 20, instead of 21. I realize even if that seat opens up my chance at the UG is pretty small, since I'm currently only a Gold (Although this flight will put me over to Plat). I'm just curious why there is the difference between the two sites.