As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
VNAV DISCONNECT IN FLIGHT, SPEED AND ALTITUDE DATA WAS TEMPORARY UNAVAILABLE IN THE FMC. EVENTUALLY THE DATA WAS RESTORED AND WAS ABLE TO UTILIZE VNAV. LAST 1 & .5 HRS WAS FINE. VNAV OPERATED NORMALLY. ACFT GROUNDED. ACCOMPLISHED FMCS FIM TASK 34-61 NR 801, NO FAULTS OR FAILURES. FMCS BITE CHECKS & OPS CKS OK REF AMM 34-61-00-710-801.