As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: L3 LAVATORY SMOKE DETECTOR INDICATED SMOKE DURING CRUISE FLIGHT. NO SMOKE WAS NOTICED BY FLIGHT ATTENDANT UPON INSPECTION. WARNING WAS ON FOR A FEW SECONDS ONLY. MAINTENANCE ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK OF THE L3 LAVATORY SMOKE DETECTOR WITH NO FAULTS NOTED.