As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNAVINVALID-RERF- MESSAGE, IN CRUISE. LOST ALL FUEL + TIME PREDICTION-INSERTED COST INDEX PER SH 11.080 P.11 AND RESTORED VNAV SUCESSFULLY. GROUNDED - YES. PERFORMED B737-800 FIM 34-61 TASK 807. CYCLED FMCS CIRCUIT BREAKERS. NO DEFECTS NOTED.