As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TEST FLIGHT WITH AUTOPILOT ENGAGED, AIRCRAFT EXPERIENCES PITCH OSCILLATIONS BETWEEN +/-20 TO 800 FPM VSI. PITCH DISCONNECT HANDLE PULLED IN FLIGHT AND REVEALED LAG IN LEFT SIDE PITCH CONTROL SYSTEM. PERFORMED FLIGHT CONTROL PATH INSPECTION AND FOUND THE LEFT ELEVATOR LOAD LIMITER BAD (CONNECTING ROD SEPARATED FROM SPRING HOUSING). REPLACED FAILED LOAD LIMITER WITH SERVICEABLE PART.