This has happened twice. I wonder if anyone else has experienced it. I know I cannot exit the car and lock the door with the key in the car, but........ I got out of the car, my purse with the key in it laying on passenger seat... and I went in the house and came out to get in the car and my door was locked! Fortunately, the back door was still unlocked so I got in, reached up and unlocked the front door. First time it happened was a couple months ago. Forgot all about it until today. Exactly the same thing: Got out, left purse on front seat, delivered a coffee to my daughter, came out and my door was locked! Back door unlocked, so I again reached up and unlocked the front door. IMPOSSIBLE, so it would seem. But TWICE makes me bellieve it somehow is possible. Ideas, anyone?
Just a guess but since another door is still unlocked it would appear it's not an electrical glitch. Any chance you are manually moving the lock button/lever near the handle on that door as you open it, and it's locked when you then close that door?