I've had the same issue from time to time, where it just resets on its own. I don't know why. It's become SOP that I check it when I start the car. Last year or three, it's been pretty good, with minimal resets.
Keep the car on a batter tender possibly. I've had the car just barely start and getting the voltage that low reset everything. Very obvious in my car as it was originally a Canadian car so defaults resets everything to Celsius and Kilometers, but also resets some of my driver assist settings like my shift light and launch control settings.