As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FILTER WAS REMOVED FOR A 100-HOUR INSPECTION. PRIOR TO CUTTING THE FILTER OPEN, A FOREIGN MATERIAL WAS VISIBLE ON THE OPENING OF THE FILTER. FURTHER INSPECTION REVEALED THE FOREIGN MATERIAL WAS A SEAL USED BETWEEN THE TOP OF THE FILTER CAN AND THE ELEMENT. AS A RESULT, UNFILTERED OIL COULD BE RETURNING TO THE ENGINE ALONG WITH THIS LOOSE MATERIAL.