Originally Posted by Fly Me To The Moon

Yes, as you described. I do not know what to share with you. It just works (worked) for me up until approx 6 weeks ago.

Another example which has happened at least twice for me in the past year: on premium econ for TPE-HKG flight, but my boarding pass gets update to the blue colour. Yeah! Business Class. I get assigned a seat which I do not like, so I go to the computers in the Lounge to select a new seat. The boarding pass on my phone gets updated to the new seat. At boarding, my mobile boarding pass is scanned and I still get a beep (apparently because they need to enter something into the computer). At the same time, they notice that I had been upgraded and give me a new boarding pass that had been preprinted. They then scan this boarding pass, get a red beep, and then further notice that the seat assignment on my mobile boarding pass is not the same as on the paper one. I then tell them that I had changed seats after they had upgraded me.