As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE VTK AND MAP FLAGS ON CAPTAINS MAP DISPLAY 2 MINUTES LATER AND PRIOR TO QRH PROCEDURE FLAGS WAENT AWAY AND A MAP FLAG APPEARED ON FO'S DISPLAY ALONG WITH SINGLE FMC OPERATION IN SCRATCH PAD. PERFORMED QRH AND FO'S DID NOT RESTORE. GROUNDED - YES. REF B737-800 FIM 34-61 TASK 836 CYCLED FMC C/B FMC OPERATIONS RETURNED TO NORMAL.