In my HKG-SFO reservation, there is a line "Enjoy the added benefits of United Premium Plus." $325. Clicking on the "Learn More" link takes me to the reservation summary.
The same thing happens when I click on an available PP seat (via the "change seat" link in my reservation). Hovering over an available seat displays "...Select to view upgrade options and pricing". Clicking on that takes me back to the reservation summary as well. No offer there.
Is that a bug? A fake upsell offer?