Some 2008-2011 Ford Edge and MKX vehicles built on or before 10-25-10 may experience a popping noise when opening one of the rear doors, typically the right side, especially if the door has been closed for a minimum of 10 minutes.
The sound may be caused by the rubber bumper located on the lower rear corner of the rear door inner panel. Suction between this bumper and the body side panel may cause a pop when the door is opened id there is a narrow seal gap between the door and body.
On the affected rear door, remove the rubber bumper and insert a rubber plug into the exposed hole. While the TSB notes to place a small Phillips or Torx screw driver in the center hole of the rubber plug to aid in installation, to minimize the potential for tearing the plug, use a narrow blunt drift instead.