As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB OF FLIGHT 7621 CREW REPORTED A THRUST REVERSER UNLOCKED MESSAGE. CREW RETURNED TO BUF AND FLIGHT LANDED UNEVENTFULLY. PASSENGERS WERE DEPLANED NORMALLY. UPON INSPECTION OF THE THRUST REVERSER SYSTEM ICE BUILDUP WAS FOUND ON THE THRUST REVERSER PLUNGERS AND WAS REMOVED. A SATISFACTORY OPERATIONAL CHECK WAS PERFORMED AND AIRCRAFT WAS RELEASED FOR SERVICE.