I'm looking to book LAX-EWR on 6/24 on AA. Lowest price is ~$250, but I can piece together 2 one-ways with a 47 minute layover in PHX for $137 (AA2318 + AA1439). Neither the AA website nor any OTA's will offer this combination of flights when I search LAX-EWR. I did confirm with an AA agent that it does not violate minimum connections times for PHX (she couldn't quote for me exactly what the MCT is, but said the system allows it for this combination of flights). However, the agent said we probably can't check any bags and there is a risk that the itinerary will get automatically cancelled even up to an hour before the flight. She couldn't explain why though - something about "pricing rules won't allow it."
AFAICT, this isn't a hidden city because I intend to take both legs of the flight. And if it doesn't violate minimum connection times, what else could the airline use as justification to cancel the itinerary? If AA issues a valid booking number can they cancel it for any reason? Does any part of it violate the airline's contract of carriage?