Assuming it was YYZ-ORD UA operated flight, on the surface, believe you are correct
But using
UA bag claculator
*G gets 3 bags North America / Canada to Japan -- +1 over the non-status customer (economy)
but change the destination to PEK or PVG and just two bags for non-status AND *G, third bag 200CAD
Beleive it is a UA system error and I would submit a claim at
https://united.com/refunds