First, keep that screenshot as I am certain that AA will correct the display in fairly short order.

The box should not be branded as "Flagship" if it is not "Flagship" OP ought to immediately call AA and ask about FL and FFD access. If the answer is "yes" ask to have the PNR annotated. If it is no, ask to be moved to the 6:30 PM flight. It's only 30 minutes later and is clearly 3-class. It's also roughly double the price, so cancelling & rebooking isn't what OP is looking for.