It really wasn't a big deal but since AC flies domestic J aircrafts on YVR-YUL, the only way to avoid it is to go via YYZ and good thing AC has that 1 stop YVR-YUL flight. It's making us stay on the plane which is the stupid part.
Today I made sure he booked it as 2 seperate segments for both YUL-YVR & YVR-YUL on my new ticket.