As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TRANSITION TO CRUISE, PILOT NOTICED AN ODORLESS VAPOR/MIST EMANATING FROM THE HEAT/DEMIST SYSTEM. RETURNED TO BASE TO HAVE MAINTENANCE CHECK IT OUT. NO DEFECTS NOTED IN SYSTEM AND COULD NOT REPRODUCE CONDITION AFTER GROUND RUN AND MAINTENANCE FLIGHT. SUSPECT WATER IN BLEED AIR SYSTEM AFTER ENGINE WASH.