As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED A LEFT THRUST REVERSER UNLOCK MESSAGE. THE AIRCRAFT RETURNED TO AIRPORT AND LANDED WITHOUT INCIDENT. MAINTENANCE TROUBLESHOT, REMOVED AND REPLACED THE LEFT THRUST REVERSER CASCADE USING THE AIRCRAFT MANUALS. CHECKS WERE ACCOMPLISHED USING AIRCRAFT MANUALS AND AIRCRAFT RELEASED FOR SERVICE.