As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED A LEFT HAND THRUST REVERSER UNLOCKED CAS MESSAGE AFTER TAKEOFF. CREW FOLLOWED THE QRH AND RETURNED TO CAK WITHOUT INCIDENT. MAINTENANCE INSPECTED AND CLEANED THE FLEX SHAFT LOCK UNIT. MAINTENANCE OPS CHECKED THE LEFT HAND THRUST REVERSER IN ACCORDANCE WITH THE AIRCRAFT MAINTENANCE MANUAL. AIRCRAFT WAS RELEASED FOR SERVICE.