I observed the same thing for my ORD-PVG flight a few weeks ago. Luckily, I got op-up because another passenger had the same seat assignment in Premium Plus section. FA brought a new boarding pass and told me that I did not deserve the op-up because of the low fare (G). Your observation is consistent with my observation for ORD-PVG. This may suggest that op-up may be based upon fare paid, not the status, although this board strongly believes that the latter is the case.
Cheers.

Hi all. Writing this from somewhere over Alaska. While I appreciate all of you guys cheering for me in this thread, unfortunately I’m sitting in seat 21J, in the e+ section ☹️

Like many of you, I’m quite perplexed about what happened, so maybe someone can shed some light on it?

By the time I got to the gate in LAX about 1 hour before the flight there were 7 seats blocked. the gate agent in LAX was paging a lot of people. There were so many people that I couldn’t track how many where coming from standbys and how many were not on the standby list, all the while, 7 seats were still blocked.

Then about 40 mins before departure all 7 blocked seats disappeared in one shot, and then a bunch more standbys cleared. The moment the 7 blocked disappeared I knew I had no shot and boarded.

the lead FA on board came to my seat to thank me for being a 1K. I saw her make one other stop in the e+ cabin and it looked like there were 5 people total on whatever list she was reading from. My best guess at this stage is that either all 7 people were on a flight which misconnected, or I was too far down the list on a K fare for make the op-up?

side note: my fiancé is in J due to a GPU (she had to change her plans after we booked and W was the only fare available, with an easy GPU). She came back to see me to say that there are still empty seats up there and that they should upgrade me. I had to tell her that’s not how it works.