As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING CRUISE, THE NR 1 ENGINE EXPERIENCED AN RPM DROP, THE ENGINE WAS SHUT DOWN. AIRCRAFT RETURNED TO POINT OF DEPARTURE. POST-FLIGHT INSPECTION FOUND A FEATHER RESERVOIR OIL TRANSFER O-RING PINCHED. THE O-RING WAS REPLACED AND THE AIRCRAFT RETURNED TO SERVICE.