Jeep lights flash randomly hours after car is off

I have a 2000 Jeep V8 Grand Cherokee Laredo with 90,000 miles on it. Yesterday, more than four hours after the car had last been driven, I noticed that the headlights were coming on and off, sometimes with the running lights and sometimes without. Sometimes they'd stay on for as long as a minute, sometimes they'd just flash. There was no pattern to it. As they've been since I first bought the car, the headlights were in "auto" mode, where they come on and off depending on available light. I turned the car on and off, but the flashing did not stop until I switched the headlights to "off."

Any ideas as to why this is happening?