What was found
(CAN) DURING DESCENT THROUGH FL170, N1 = 50 PERCENT, 1 ENGINE ACCELERATED TO MAX POWER TRIGGERING THE N2 OVERSPEED RED WARNING. THE IDLE POWER WAS SELECTED BUT THE ENGINE STAYED AT FULL POWER. AFTER APPROXIMATELY 2 SECONDS THE ENGINE RETURNED TO IDLE AND NORMAL OPERATION WAS RETURNED. AN UNEVENTFUL LANDING WAS MADE. CUSTOMER REQUESTED MRT TO PERFORM ENGINE DOWNLOAD AND INITIAL TROUBLESHOOTING.