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 AMBER MESSAGE AFTER TAKEOFF. CREW FOLLOWED THE QRH AND RETURNED TO TRI WITHOUT INCIDENT. MAINTENANCE REMOVED AND REPLACED THE POWER DRIVE UNIT IN ACCORDANCE WITH THE AIRCRAFT MAINTENANCE MANUAL. AIRCRAFT WAS RELEASED FOR SERVICE.