As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TUL- ON FLIGHT 4207, RECEIVED A EFIS COMP MON CAUTION MESSAGE WITH A DISCREPANCY NOTED IN THE ALTIMETERS. PERFORMED CHECKLIST AND DETERMINED THAT IT WAS A CAPTAIN'S AIR DATA PROBLEM. DISCONTINUED RVSM OPERATIONS. MAINTENANCE CYCLED AIRCRAFT POWER, AND PERFORMED ADC BITE TESTS. BITE TESTS CHECK GOOD. AIRCRAFT RETURNED TO SERVICE. NO PARTS REPLACED.