Edit a Route and the edited (inserted) Via Point and resulting new Route segment becomes a Direct Route segment. Nothing I have found will alter that condition.
Also, check your routes carefully, sometimes the Direct segment is only a partial segment.
If you see this, insert a new point just before or after the troubled part and delete the old via-point solves it for me in windows.
You can also move the existing viapoint futher on the road to the point the direct stops.