When it is shut off and parked sometimes the running board lights along with the radio and interior lights will just turn on and drain the battery. this normally happens when it is wet out side.
interior and running board lights and radio staying on draining battery on 2000 Ford Excursion
I would look at your GEM module under the dash and see if there is any water intrusion. This can cause intermittent electrical issues, especially when wet.
My did the same thing, check the rear doors, adjust were the sensor is. After time I think they get lose and need adjusting.