It's quoted that much on Google Flights etc., but I successfully booked at $2122 on AC.com for SFO-YYZ-PVG-YYZ-SFO. The price shows up higher, but after you click "I accept, Purchase" on AC.com I got a notification that the price for the itinerary has changed and it's now lower.
The fare basis is the same -- PLUNN -- so not sure what's going on, but I was in fact charged $2122.