As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DESCENT COWL VALVE OPEN LIGHT REMAINED BRIGHT BLUE WITH AMBER TAI INDICATION ON #1 ENGINE AFTER ANTI - ICE SWITCH POSITIONS TO OFF. GROUNDED - YES. ENGINE ANTI ICE VALVE STUCK OPEN, CYCLED ANTI ICE VALVE. ENGINE RUN COMPLETED. ANTI ICE VALVE AND SWITCH OPERATION NORMAL. REF B737-800 FIM 30-21 TAK 804.