As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LT ENGINE RT MAGNETO FAILED. INVESTIGATION FOUND THE MAGNETO BEARING HAD COLLAPSED. HEAT GENERATED DISCOLORED THE CAM ASSEMBLY AND MELTED THE PLASTIC BLOCK ON THE CONTACT ASSEMBLY CAUSING THE CONTACTS TO STAY CLOSED. SUSPECT CAUSED BY INCORRECT LUBRICATION OF BEARING.