As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT ENGINE, RT MAGNETO FAILED. MAGNETO WAS REMOVED AND SENT FOR REPAIR. MAGNETO WAS DISASSEMBLED, FOUND BEARING WELDED TO ROTOR SHAFT AND INTERNAL COMPONENTS DAMAGED BEYOND REPAIR. PREMATURE FAILURE OF BEARING DUE TO LACK OF LUBRICATION OR DEFECT. MAGNETO HAD 494.6 HRS TT SINCE REMANUFACTURE.