Originally Posted by
pitz
A few points:
1) A J ticket with segments only confirmed in Y, means you automatically go onto the waitlist for J seating. Fare rules require that an AP J ticket have at least one confirmed J segment prior to issuance.
2) Waitlists are cleared before any upgrades are made. Hence, the upgrade priority schema as quoted by "Ben" doesn't matter. Upgrades are only for passengers who bought Y tickets and want to travel in a class of service they strictly didn't pay for. Waitlists are for people who paid J fare (either cash or points) and were not able to be confirmed in J at the time of booking.
The terms of a mixed cabin Aeroplan reward are clear that you can "request an upgrade" at the airport for J seat. Everything else on this forum including info from AC reps and experience from other passengers says that they go on the upgrade list. OP's experience that their upgrade didn't clear when plenty of other upgrade requests cleared is a pretty good example of how they are handled on the upgrade list, differently than if someone bought a J ticket and was waitlisted for a seat.
Yes, the person has paid the points for J, but AC sets the rules and AC treats it as an upgrade, so there's a decent chance it may not clear.