As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FL 320, LOUD THUD HEARD FROM JUST BEHIND COCKPIT DOOR. MAIN CARGO DOOR WARNING LIGHT ON S/O PANEL ILLUMINATED. COMPLETED EMERGENCY CHECK LIST. DEFERRED MAIN CARGO DOOR PER MEL 52-4-1 FOR NON PRESSURIZED FLIGHT AND ASSIGNED DMI 2259. FOUND FWD LATCH PIN ACT ON MAIN CARGO DOOR AT FAULT. REMOVED AND REPLACED ACTUATOR AND OPS CHK OK PER M/M 52-32-01. THIS CLEARS DMI 2259.