When car has been stopped, in traffic or parking lot, the parking/emergency brake has engaged automatically (NOT engaged manually or intentionally by driver) and will not disengage automatically when accelerator is pressed to go forward. It is difficult to disengage the brake when this occurs. This has happened on 3 occasions. The safety risk for crash includes being hit from behind if brake engages unintentionally in traffic or on highway, or potentially sudden unintentional stopping while driving at moderate or high speeds. The issue was reported to dealer after twice occurring and full DTC check performed. Dealer says all diagnostics normal and could not identify any problems with parking/emergency brake or Collision Mitigation Braking System. The issue has occurred one time since the dealer inspection. The red light on the emergency break switch (console) comes on when this occurs, but no prior warning lamps or messages.