I never got a straight answer on why the diversion happened. Pilot didn't really explain it, Admirals Club didn't have a clue, gate agents were surprised we showed up, and the AA Plat line doesn't know now. There was talk of a fuel issue. The reason why I did end up being stranded overnight is because the original crew went over their hours and they couldn't find a replacement crew to come through once the plane had been refueled.