As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LAVATORY D3, SMOKE ALARM WITH NO SIGNS OF SMOKE. ALARM TURNED OFF ON IT`S OWN. NO SMOKE OR ODOR WAS TRACED BY F/A. LOOKED FOR ANYTHING SUSPICIOUS INCLUDING UNDER SINK AND WAS UNABLE TO LOCATE ANYTHING SUSPICIOUS. NO HISTORY FOUND. REF TSM 26-14 TASK 801, SINCE ALARM WAS VERY BRIEF, AND STOPPED THE FAULT IS CLEARED. NOTE PASSENGER WAS INSIDE WHEN ALARM SOUNDED.