As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT CRUISE RECEIVED CAPT ALTI FAULT ECAM WITH COMMENSURATE INDICATIONS ON THE PRIMARY ALTIMETER INCLUDING OFF FLAG FOLLOWED BY ERRATIC ALTITUDE INDICATIONS VARYING BY UP TO APPROXIMATELY 1000 FEET FROM FO ALTIMETER. REFERENCE QRH FOR REQUIRED RVSM EQUIPMENT WE DESCENDED TO FL 270 AND DIVERTED TO KOKC FOR FUEL AND MX REPAIR. AMM: 34-12-21-04, REPLACED CAPT MAIN ALT 2FL1. BITE AND BARO CORRECTION TEST NORMAL. ACFT OK FOR SVC.