As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: FORWARD LAVATORY SMOKE DETECTOR WARNING DURING FLIGHT. WARNING LASTED ABOUT THREE SECONDS. FORWARD LAVATORY WAS VACANT AT THE TIME. NO EVIDENCE OF SMOKE REPORTED BY FLIGHT ATTENDANTS. MAINTENANCE PERFORMED SYSTEM BITE TEST PER AMM 26-17-00 WITH NO FAULTS NOTED.