As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: UPON SHUTDOWN OF AUXILIARY POWER UNIT, LAVATORY SMOKE DETECTOR ACTIVATED FOR APPROXIMATELY 4 MINUTES. FLIGHT ATTENDANT REPORTED IT WAS FORWARD LAVATORY, NO REPORTED EVIDENCE OF FIRE. REPLACED FORWARD LAVATORY SMOKE DETECTOR PER AMM 26-14-01.