I understand that Diamond Guaranteed Availability means rack rate and that it isn't available during major events such as the superbowl, but does it go away for just an ordinary football game? And when is this block supposed to be put into place in the hyatt.com reservation system?

I'm asking because yesterday I checked availability on hyatt.com, went off to firm up some other travel plans that I was trying to coordinate with the Hyatt stay, and returned about an hour later after some website issues to discover that the hotel suddenly went from having virtually all room categories available for all rate plans (various government, AAA, AARP as well as normal and advanced purchase) to showing a red text that the hotel either wasn't yet open for reservations or was sold out when I was logged in as a Diamond instead of showing me the page with the guaranteed availability rates for a few room types. This is for a late September weekend, so I'm well before the 48/72 hour deadline but close enough that any blackout should have been implemented long ago if it was officially approved as the game schedule was surely set in stone long ago.

I've been checking back and a few times the website seemed to let me start to book a good rate only to give me the red error message page later. If I try for longer stays covering the date in question, I can see lots of availability, even sometimes for all of the rate plans. However, if I click further, I notice that government rates disappear once again and the AAA/AARP rates are nonrefundable/prepaid with thirty day cancel policies, despite there being no warning of this unless one clicks on the rate plan for the particular room. I find this scary as I would assume that AAA/AARP rates at worst are day before cancel policy with credit card guarantee. It would be very easy here to unknowingly book a prepaid/nonrefundable room as the same page shows the prepaid rates with a clear red warning at the top of that block rates that they are indeed nonrefundable but this message does not appear for the AAA/AARP type rates.

Is this standard Hyatt policy with respect to the Diamond Guaranteed Availability benefit? I.e., can a hotel go from lots of availability to a blackout for the room guarantee a few weeks before an event that doesn't seem to be so major? Or could I be seeing no Diamond Guaranteed Availability rates because of some minimum stay requirement? Is there any point in my continuing to check for availability? Or could this be just a website issue/glitch? The property is one that Hyatt recently purchased, so this could be their first football season under the Hyatt flag.