This issue is not reproducible.
When using a distance based travel mode, for example, the Driving Distance travel mode, the Total_TravelTime field does not populate by default. This is because Total_TravelTime fields are only populated for impedance attribute and accumulate attributes. The impedance attribute of the Driving Distance travel mode is Kilometers, and the TravelTime attribute does not accumulate by default. Thus, it does not display Total_TravelTime. If user wants to get the Total_TravelTime field when using the Driving Distance travel mode, they could add TravelTime to the accumulateAttributeNames parameter.