I have a (possibly related) challenge that I'm unable to overcome. A few weeks ago I booked a ticket to Europe and applied PlusPoints to upgrade to Polaris. Since that time, I had several upgrades clear, leaving me with insufficient PP to upgrade this later itinerary. Since it is a B fare, I decided to go in and cancel the PP request (no problem) and apply miles instead (again, no problem). Miles were deducted, and the PP requested number decreased as expected.

However, a few days later I noticed that the App still showed "Upgrade -- Skipped (insufficient credits)". Curious, I called the 1K line, spent 45 minutes on the phone with an agent, who involved both their supervisor and the mileage plus line after confirming that the system still somehow thought I was applying PP. After removing all upgrade requests for the entire itinerary, and then re-applying them, she said that things looked good on her end.

Now, almost a week later, I am still seeing "Upgrade -- Skipped (insufficient credits)" on the App, and there is no waitlisted segment showing on united.com. I'm paranoid that I'm going to be skipped over if PN space opens up, so I'll probably call back once state-side in a few days...