As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: SMOKE LAVATORY SMOKE MASTER WARN ON ECAM FOR APPROX 5-10 SECONDS THEN RESET BY ITSELF. FLIGHT ATTENDANT NOTED NOTHING IN LAVATORY. MAINTENANCE ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK OF LAVATORY SMOKE DETECTION SYSTEM PER AMM 26-17-00 WITH NO ECAM OR WARNING LIGHT FAULTS NOTED.