As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ENGINE OIL PRESSURE WENT FROM 60 PSI TO 32 PSI AFTER TAKEOFF WHEN THE AIRCRAFT WAS LEVELED OFF FOR CRUISE. PILOT RETURNED AND LANDED SAFELY. ENGINE HAS BEEN GROUND RUN TWICE AND CHECKED. COULD NOT DUPLICATE ON GROUND. AIRCRAFT RETURNED TO SERVICE. NO FURTHER REPORTS.