As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT, THE CREW RECEIVED A LAV SMOKE CAS MESSAGE. THE FLIGHT ATTENDANT INSPECTED THE LAV AND THERE WAS NO SMOKE OR EVIDENCE OF FIRE OR SMOKE. UPON ARRIVAL, MAINTENANCE INSPECTED AND DEFERRED THE LAV SMOKE DETECTOR IN ACCORDANCE WITH 26-4 CODE C, MAINTENANCE FUNCTION WAS COMPLIED WITH.