As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED A LAVATORY SMOKE INDICATION ON THE EICAS. THE FLIGHT CREW FURTHER REPORTED THAT NO SMOKE WAS OBSERVED AND THERE WAS NO SMELL OF SMOKE IN THE CABIN OR COCKPIT. THE INDICATION CLEARED ITSELF AND THE AIRCRAFT RETURNED TO FIELD. MAINTENANCE REPLACED THE LAVATORY SMOKE DETECTOR. OPERATIONAL CHECKS WERE GOOD WITH NO FURTHER DEFECTS NOTED.