I have a door that is opening without the emobilizer being pushed

I have a Ford Futura 2006. The door on the drivers side passenger will lock when the emobilizer is pressed to lock. When you go to open the passenger door it will open all the doors. When locked the enteria lights will come on and the blinker lights will flash without using the emobilzer the door opens this happen every so often 20to 30 minutes.