Routes being added to layer even if route cannot be not generated

When you perform a "Directions From 2 Point-Layers", if a route cannot be generated (start/end points cannot be found on the network), the route information is filled in with the information from the last succesful route generation.

For example, I use two files, each with 100 points. I set the start and end id fields to be a numerical id of the point in each file. When I run the process, only two of the routes can be generated, those with point ID 11 and ID 56 (due to other points being too far from the network). The resultant layer contains 89 routes, starting with a route from the points with ID 11, and then there are 45 identical routes to that one, before the one for ID 56 gets a different route, and then there are 33 identical routes to that one.

It should be the case that when a route cannot be generated, no feature is added to the layer.