As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT CRUISE ALTITUDE, ENROUTE, THE R REV UNLOCK MESSAGE ILLUMINATED. THE FLIGHT CREW COMPLETED THE QRH AND DETERMINED THAT THE THRUST REVERSER WAS NOT ACTUALLY DEPLOYED. FLIGHT CREW ELECTED TO PERFORM AN AIR RETURN. AN OTHERWISE NORMAL APPROACH AND LANDING WERE MADE. MX INSPECTED THE ACFT, DEFERRED THE RT THRUST REVERSER AND RELEASED THE ACFT FOR SERVICE.