Why am I not on the upgrade list for my flight

I am traveling on UA 838 from BKK to NRT and onwards to SFO tomorrow and just completed the online check in.

I had previously applied for a mileage plus upgrade (co-pay) and received an email that it cannot not be confirmed at this point. The email stated that I am added to the upgrade list but after checking in, I cannot see myself on that list.

Does anyone have similar experiences?

Oh and I should add that I am a United 1k - if that makes any difference