jund

I am just wondering if anybody had this problem before. A week ago I noticed while cruising that my rear door locks were up/unlocked which is unusual since they usually automatically lock when the car moves, so I tried to lock them via the central locking button on the center of the dash but to no avail. So i parked and tried it again and was unsuccessful, the front locks and unlocks with the central locking with no problem. I turned the car off and turned the alarm on and this time the rear locks locked and unlocked via the remote fob(arming and disarming). So I went to bmw and they all checked the fuses and everything were fine but still could not get the rear lock work via central locking inside the car. By the way i can unlock them via the central locking but cant do the lock function via this way. So they suggested to come back and leave the car for further evaluation and for possible replacement of door lock "actuators". so I got home and fiddle with the i drive( door lock function/choices), checked and unchecked the " lock doors when the car move" function and to my surprise i had it working again( rear locking when car moves and able to lock and unlock the via central locking button inside the car). For a week It has been working off and on until this afternoon. I checked the fuses and fiddled with the i drive with no luck. I probably have to have bmw check the car again and diagnose the problem. I think this is computer related/glitch vs. mechanical which they suggested before. What do you all think? Any suggestions, and has anyone had this same problem before?