As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) SHORTLY AFTER REACHING CRUISE ALTITUDE THE RPM ON #1 ENGINE REACHED 14,500 RPM. THE PROP SYNC. WAS TURNED OFF AND THE RPM RETURNED TO NORMAL CRUISE RPM. A SHORT WHILE LATER WITH PROP SYNC. ON THE RPM AGAIN INCREASED, A PRECAUTIONARY LANDING WAS CARRIED OUT. POST FLIGHT INSPECTION FOUND THE FCU FAULTY AND THE FCU WAS REPLACED AND THE AIRCRAFT RETURNED TO SERVICE.