Flight 482 is 737
Seeing that AS 482 is one of the models of 737, checked bag should have been allowed. AS computers of late, has had some hiccups of late, and perhaps, the system was malfunctioning at the time of your bag check, unable to find your record in printing your bag tags. or your check-in time within 40 minutes cut off and no longer available for bag check. (this policy is a bit annoying).
Good that you were able to find a way to making things work, and your destination on-time.
Jiburi