It violates MCT which should be enough to force AC to find an alternate route free of charge (and potentially be forced to open up space on their own metal for YYZ - SFO). Do some research before you call in to find potential alternatives since you should be able to handpick them in this situation assuming availability.

EF shows 60 minutes as the MCT for D/I on United (or potentially 45 it's unclear but a violation either way).