Originally Posted by
intuition
...
The second change is that now all segments are open for instant upgrade. (And maybe that is the change that triggered my wait-listed segment to suddenly become open for bids)
...
Returning to the question of when waitlisted segements are also open for bidding.
I think it is tied to the instant upgrade process.
My waitlisted upgrade segment has returned to "Not eligible" at the same time as "Instant upgrade" has disappear. If I check the seatmap of the business cabin on this flight, one more seat is now taken. So what I believe happened is that they released one seat to "instant upgrade", pushed an email to all and as soon as someone opted for instant upgrade, they closed the instant channel and all returned to status quo for my waitlisted segment.
There are still 10 seats in the cabin open in the seat map, so I think it it remarkable they are keeping a cupon upgrade on waitlist just a few days before take-off.