Thanks for clarifying! A couple points.

You should not make any changes to OSM to "fix" some other router (or navigator, map, app, etc.). OSM contains the data and it should be correct and accurate. If another application is not using it correctly - it should be fixed there.

You say that GraphHopper cannot create a route. Well, it sounds like it shouldn't - this road is not accessible to anything that is not buses. Therefore, `motor_vehicle=yes` would not be correct.