As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
VTK DISPLAYED PILOT'S ND, BLANK CDU ON FO SIDE. RAN QRH SELECTED BOTH ON RT DISPLAY RESTORED WITH BEARING FOR BOTH FMC'S INDICATER RETURNED TO NORMAL OPS. THIS SEQUENCE OCCURRED 3 TIMES. LAST TIME EVERYTHING WORKED NORMALLY FOR REMAINDER OF FLIGHT. ACFT GROUNDED. ACCOMPLISHED OPS RESET IAW AMM 34-61, TASK 836.