I have a 2008 S5 and am having an issue with the auto-lock. I have the auto-lock turned OFF in settings, but sometimes (and it's totally random so I never know when it'll happen) the car still locks on its own when I close the driver's side door. Obviously this is a problem with a push-start because if you leave your keys in your bag, intending to go around and grab it, and it locks, you're effed.

Any thoughts on what could be causing this?