As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT FMC FAILED AT FL340 LEVEL FLIGHT, VTK DISPLAYED ON CA ND NO FMC PROMPT ON MCDU. SYSTEM FULLY RECOVERD AFTER 30 SECONDS. ACFT GROUNDED. FIM 34-60 TASKS 801 & 837 APPEARS TO HAVE BEEN AN INTERMITTENT FAULT FMC OPERATIONAL TEST IAW AMM 34-61-00 NORMAL HAS NO OTHER RECENT HISTORY.