As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: LAVATORY SMOKE LIGHT ILLUMINATED AT CRUISE WITH MASTER CAUTION LIGHT. EXTINGUISHED AFTER 5-10 SECONDS. FLIGHT ATTENDANTS REPORT NO FINDINGS AND COULD NOT SPECIFY WHICH LAVATORY. PERFORMED SATISFACTORY TEST OF LAVATORY SMOKE SYSTEM.