As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE LT AUTO FEATHER AFX ANNUNCIATOR STARTED FLICKERING THEN EXTINGUISHED COMPLETELY AND THEN EVEN PRESS TO TEST WOULD NOT FUNCTION. PERFORMED AIR RETURN WITHOUT FURTHER INCIDENT. MAINTENANCE COULD NOT DUPLICATE AND SYSTEM OPERATIONALLY CHECKED GOOD. AIRCRAFT RETURNED TO SERVICE.