Performed a leak search on direct vent LP gas logs. I checked from tank to logs shutoff valve and no leak. The Burner assemblyâ€™s gas valve/regulator has malfunctioned. When the unit is running the valve is releasing gas and when you shut the unit off the valve is not closing all the way letting gas to be released into the home. The unit needs to be replaced or repaired depending on availability of parts or homeowners decision.