As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE DETECTOR AURAL ALERT, SMOKE INDICATION DISAGREES WITH LAVATORY CONDITION AT ABOUT 6 HOURS, 45 MINUTES INTO FLIGHT. AFTER 2 MINUTES, NO SMOKE OBSERVED BY FLIGHT ATTENDENT. ACCOMPLISHED A LAVATORY SMOKE DETECTION OPS TEST IAW AMM DMC-B787-A-26-13-00. SMOKE DETECTION SYSTEM CHECKED NORMAL. NO FAULTS NOTED.