Sometimes it works. Sometimes it doesn't work and killing and restarting the app makes it work. Sometimes it doesn't work and nothing will make it work.

I even had a new one this week where it updated my new seat assignment, but blanked the QR code forcing me to get a new paper BP regardless.

There seems to be no rhyme or reason. Had one recently where both a coworker and I got a gate upgrade on the same flight, standing next to each other in YYZ and both on iPhones, and his BP updated mine did not.