As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING AIRCRAFT OPERATION THE CREW REPORTED A LAVATORY SMOKE WARNING. THE RETURN TO SEAT SIGN IN THE LAVATORY WAS FOUND TO BE MALFUNCTIONING AND THE BULB WAS REPLACED. A SATISFACTORY OPERATIONAL CHECK WAS PERFORMED AND AIRCRAFT WAS RETURNED TO SERVICE.