As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DESCENT FROM PFN-ATL, AT APPROXIMATELY 13,000 FEET THE LEFT ENGINE FEATHERED UNCOMMANDED WITH AN INITIAL RISE UP TO APPROXIMATELY 120 PERCENT THEN POWER WAS LOST AND THE PROPELLER FEATHERED. THE QRH WAS COMPLIED WITH AND AN EMERGENCY WAS DECLARED. THE AIRCRAFT DIVERTED TO SG AND LANDED SAFELY. MAINTENANCE WILL BE REMOVING AND REPLACING THE LEFT ENGINE.