As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SUP - SIGNIFICANT EVENT - SUSPECTED AUTOFEATHER - UPON APPROACH WITH AUTOFEATHER ARMED BOTH TOQUE GAUGES AT 1000 THE RIGHT HAND SURGES BETWEEN 500 & 1500 LBS. OF TORQUE. FEELS LIKE AN AUTOFEATHER TEST. THIS CONTINUED UNTIL POWER WAS REMOVED, APPROXIMATELY 500 LBS. OF TORQUE. MAINTENANCE REMOVED AND REPLACED THE LEFT HAND ENGINE HIGH PRESSURE SWITCH. IAW MM 61-21-01-201. PERFORMED AFX OPERATIONAL CHECK IAW MM 61-21-00. NO DEFECTS FOUND. COULD NOT DUPLICATE FAULT.