As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE CAS MESSAGE ILLUMINATED FOR THE LAVATORY AND EXTINGUISHED WITHIN 15 SECONDS DURING DESCENT. NO SMOKE OR FIRE WAS DETECTED DURING INFLIGHT INSPECTION BY FLIGHT CREW. REMOVED AND REPLACED THE SMOKE DETECTOR. OPS CHECKED GOOD IAW AMM 26-10-00. NO FURTHER DEFECTS NOTED.