As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT CRUISE BOTH LNAV / VNAV DISCONNECTED AND WAS FOLLOWED BY AN AMBER VTK FLAG ON THE CAPTAINS DISPLAY AS WELL AS BOTH CDU'S WENT TO MENU MODE AFTER APPROXIMATELY 20 SECONDS EVERYTHING SELF CORRECTED AND ALL WAS NORMAL. GROUNDED - YES. ACC FIM TASK 34-61-TASK 836 RESET FMC REPAIR CONFIRMATION CONFIRMED. OPS TEST PASSED, SEAMC DAVE NOTIFIED.