As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) EXHAUST VALVES ON NR1 CYLINDER (P/N 913425) AND NR2 CYLINDER (P/N 913435) WERE FOUND NOT SEATING PROPERLY, ALLOWING BLOW BY. SEAT REFACED AND NEW VALVES INSTALLED. NR1 AND NR2 CYLINDERS UNSERVICEABLE DUE TO BLOW BY. WEAR ON MATING SURFACES BEYOND ACCEPTABLE LIMITS.