As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENROUTE FROM KONT TO KPHI AND APPROACHING 8,000 AUTOPILOT WOULD NOT DISENGAGE. AIR TURN BACK TO KONT WITH EMERGENCY DESCENT. LANDING WAS UNEVENTFUL WITH NO ADDITIONAL PRECAUTIONARY ACTIONS. UPON ARRIVAL AIRCRAFT WAS GROUNDED FOR UNSCHEDULED MAINTENANCE. WORK IN PROGRESS