As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: WHILE ENROUTE THE LAVATORY SMOKE DETECTOR WARNING WENT OFF FOR 3 SECONDS THEN CLEARED. FLIGHT CREW FOUND RIGHT AFT LAVATORY HALON BOTTLE DISC RED BUT NO EVIDENCE OF SMOKE, FIRE OR DISCHARGE. MAINTENANCE REPLACED FIRE EXTINGUISHER IN AFT LAVATORY PER AMM 26-25-41.