As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) THE CREW HAS REPORTED SEVERAL TIMES THAT DURING THE DESCENT THE LEFT ENGINE HAD A ROLLBACK FROM THE 52% RANGE TO APPROXIMATELY 25%. EACH TIME THE POWER LEVER WAS ADVANCED TO GET THE SPEED BACK UP. THE EDS/EDU DOWNLOAD WAS SUBMITTED AND NO IRREGULARITIES WERE NOTED. TROUBLESHOOTING IS ON-GOING.