As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE, LT FMC FAILED AND DISPLAYED VTK FLAG ON CAPTAIN'S ND. FMC THEN RESUMED NORMAL OPERATION. ACFT GROUNDED. COULD NOT DUPLICATE DEFECT. ACCOMPLISHED FMC BITE TEST IAW FIM 34-61, TASK 801. NO FAULTS LOGGED ON GROUND OR LAST FLIGHT LEG. ACFT OK FOR SERVICE.