I was just looking at one of my reservations, and looks like I've also been hit by a change to a single cabin rouge A321 and a downgrade. Had a reward flight booked YUL-YYT that was originally an AC Express E175, moved to a rouge 319, and now moved to a single cabin rouge A321 and downgraded to economy. It's on a UA issued reward ticket, so unfortunately this may be a hassle to try to get resolved.