Originally Posted by
aacar
I've seen this happen on a mixed-cabin itinerary (e.g. outbound in Main, return in First). The Sky Priority banner will show on for flights, but the boarding group will be based on the class of travel for each particular flight.
I have a future trip where this exact thing is displaying right now. Outbound I paid for a first class upgrade, inbound remains economy. Both legs have the Sky Priority banner on top of them in the app. I have half a mind to try to use Sky Priority check-in on the return leg just for kicks, but I know better.