As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED LOW OIL PRESSURE ON THE SECOND FLIGHT AFTER THE 100 HOURS INSPECTION. OIL FILTER WAS REMOVED, CUT AND INSPECTED. UPON INSPECTION, IT WAS NOTED THAT THERE IS NO OIL IN THE CENTER PART OF THE OIL FILTER. A NEW OIL FILTER WAS INSTALLED AND PERFORMED GROUND RUN AND TEST FLIGHT WITH NO DISCREPANCIES NOTED.