If the doors were fully closed and latched, then started opening on their own, I doubt the auto-reversing of the door for pinch/resistance is the cause. Its while the doors are in motion that this takes effects, once the door is fully closed or open, there is no way to sense the resistance let alone trigger the door reversing direction? I could be wrong, but this makes sense to me.
On my '02 mini-van I did find that simply dirty sticky door seals on the sliding doors would cause the resistance to auto-reverse the doors. It was solved by simply scrubbing the seals and door surfaces with soapy water. On the sliding doors, the doors slides against the seals as it closes, so sticky surfaces on the seals and door, grab the door and create resistance. Anything in the hinges and rails that doors slides along can increase the resistance.
There also might be a calibration procedure for the doors and their auto-reverse anti-pinch feature. It can't hurt to run the calibration and see if it fixes the problem, if there is a calibration procedure.
I would check the voltage of the battery and charging system, the vehicle off and running. Low voltage from a bad battery or charging system has been know to send semi-conductor electronic modules batty. Previous generations of mini-vans, windshield wipers turning on and off all by themselves, was a dead give away clue you had a bad battery. Same thing might happen with doors on the newer vans. Regardless, a quick voltage check of the electric system in different conditions and monitoring it to see if voltage drops at any point.
