In many vehicles (Mercedes, etc), the modules that fail to initialize correctly will post an error (OBDII) and will not try to reboot again until the engine is restarted.
Bad gas may make the engine miss enough to make the awd be disabled. I remember at least two cases in my old vehicle forums..
2011 Pearl White MDX Advanced
... OEM towing, 20 mm wheel adapters,
... rails/crossbars, black wheel well trims,
... side windows acrylic deflectors,
... Michelin Latitude Diamaris HP 285/45R19,
... Full size spare tire,
... 6000 Kelvin HID's
2010 Acura TL Tech.
2001 Mercedes ML 320
2005 Mercedes ML 500 AMG Package