I've been trying to get a P+C reservation at the Hyatt Regency Osaka during a sold-out day for about a week now, checking the site very frequently. 99.9% of the time it remains nothing but Guaranteed Availability; however, on two occasions I have seen full availability of all rooms show up. But by the time I call Hyatt to make the booking, all of availability is gone again.

I find it highly unlikely that so many rooms were filled so quickly on two separate occasions. Is this some kind of glitch in the matrix, or some kind of "flash availability" for the third party sites to receive price information? Whatever it is, it's very frustrating.

EDIT: Third time's the charm! The room stayed available over 30 minutes, long enough to get the P+C reservation and apply a DSU to it!