Recently the liftgate has closed unexpectedly several times while items were being unloaded/loaded from the rear of the vehicle. This caused the user to be struck by the liftgate. Someone smaller or weaker, such as a child could potentially be trapped and injured since the blockage detect function apparently fails at the same time. It has also opened on it's own while the operator was away from the vehicle and out of range of the key fob. Apparently, this is a common issue with the panoramic roof in many Cadillac models leaking water into the rear storage area of the vehicle. The control module becomes immersed in water and begins to perform unreliably, eventually failing complete as it becomes more wet. No warning tones or lamps are activated