I booked SFO-SIN-SFO this past Monday for a trip in late September. Was showing I9 all the way through. Was able to confirm all upgrades using SWU. Now award availability shows nothing for upgrade inventory.

Something definitely amiss.

I noticed the same thing happen last spring when I was getting ready to book SFO-PVG. That time I got caught on the wrong side of whatever they were doing, and upgrade availability got zeroed out when the day before it was I9.