As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 5561 - EN ROUTE LEX-CVG RECEIVED AN ANTI-ICE DUCT WARNING MESSAGE, FLIGHT DIVERTED TO BNA DUE TO INCLEMENT WEATHER. PERFORMED ENGINE RUNS AND OPERATIONAL CHECK OF THE WING ANTI-ICE CONTROL INDICATION SYSTEM. UNABLE TO DUPLICATE DISCREPANCY.