The investigative steps in this article also apply to route time and distance values not displaying for some routes.
Google Maps is used to obtain the map view and the route path. If an outlined path does not display on a map with a route, when it normally does, that means Google Maps did not return the proper data for us to display the path. The observed root cause of this problem in the past is Google not being able to properly find a road to get to an exact latitude/longitude coordinate on the route. A latitude/longitude is obtained from an address, or it can be manually input.
A similar problem occasionally occurs with a total route time and distance not appearing. These values come from Mapquest, who handles the route calculation portion of the system.
The following investigative steps should be performed for both problems.
The first step to attempt to fix the problem is to double check all of the service addresses on the route. You can even save all of them again, which will reobtain the latitude/longitude for that address.
The next step will be to remove one stop on the route, by adjusting the schedule or one-time moving it to another route, and then refreshing the map view. Do this one at a time until you find the culprit. When you find the culprit, study its location on a map view. Is it set back from an actual road, with a questionable path to get to it? See if you can adjust the customer's service address, or manually input a different latitude and longitude, to get it closer to the road.
If you have taken these steps but can't pinpoint the root problem, please contact us so we can attempt to investigate further.