As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CYLINDER (PN B2452-1) SEPARATED FROM PROPELLER ON GROUND RUN. INSPECTION SHOWED THREAD DAMAGE OF CYLINDER. AFTER DISCUSSION WITH MANUFACTURER THE LIKELY CAUSE IS DUE TO HIGH PRESSURE FROM GOVERNOR, USUALLY CAUSED BY STICKING PRESSURE RELIEF VALVE.