As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON VNAV DESCENT (USED DES NOW PROMPT) DESCENT BEGAN AT 1200 FPM. UPON CATCHING VNAV PATH, AIRCRAFT PITCHED UP IN EXCESS OF 1000FPM. CREW DISCONNECTED AUTOPILOT AND CONTINUED DESCENT IN FLCH. THIS IS A KNOWN ANOMALY THAT IS COVERED IN THE FLIGHT MANUAL, IN BULLETIN 98-08. THE PROBLEM WILL BE FIXED BY A NEW AIMS LOAD PER CHANGE ORDER PROJECT CURRENTLY IN PROCESS.