mysterious locking doors
 

I have a 2012 Mazda 3 Sport and twice over the last 2 weeks all my doors mysteriously locked with the car running and key in the ignition. According to the owners manual this isn't even supposed to be possible. Doors locking with key in ignition that is. Anyone have any idea why or what may cause this. I've tried unsuccessfully to mimic this so I could show the dealer to no avail. Any help would be appreciated. I've only had the car 3 weeks so I really don't want to disable it completely until I at least try to get a possible answer. Thanks!!