As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON A 100 HOUR INSPECTION, NR 2 & 7 CYLINDER HAD VERY LOW COMPRESSION. AFTER REMOVAL OF BOTH CYLINDERS IT WAS NOTICED THAT THE EXHAUST VALVE SEATS WERE CRACKED. THE CYLINDERS WERE REPLACED AND THE AIRCRAFT WAS RETURNED TO SERVICE.