It all has to do with the certification efforts and desires of the manufacturer. Perhaps the good folks in CYUL didn't want CL65 drivers to be cross qualified in the corporate jet versions of very similar birds?

Between airline stints I worked as a sim instructor in SAV and got typed in the GV. That jewel of a rating is good for the G350, G450, G500, G550, GV classic and hopefully even the soon to come G650. All of these birds except the classic GV have essentially identical flight decks. The classic GV (the plane the rating is based on) is an entirely different animal, but all that is required is differences training. I would argue the GV is a lot further from the others than the CL65 is from the Challenger 604/605, but that's the way the manufacturers certified 'em.