Micro vibrations, jet flying over, truck driving by, or maybe the other lights in the fixture vibrated the “broken” one enough to screw it back in. Did you know CFL bulbs can unscrew themselves from the vibrations and heat they make? Also change in temperature could cause the metal to expand or contract causing the bulb that unscrewed itself to make contact again.
Did he sing Living on a Prayer? Glad it wasn’t Third eye blind that was there.