This is my bycicle routing from Plau am See to Schwaan using latest official Navigator from Playstore and latest maps (checked this week) on Android 8.1 (Samsung tablet).
@Oldie: Please start the tour from Limbach-Oberfrohna, it will be different when the tour longer. When i start from the same place i get also the same route. @tomas: please test longer routes. From Chemnitz to 18258 Alte Weide.
in order to make route calculations fast with limited power of mobile devices you cannot include all links in route calculationon long routes - default limit is 250km and 50,000 links from each waypoint
to increase this limit you can edit file vehicle_profiles.xml
That looks, as if Navigator confuses enable and disable. One would expect the shorter route, when small roads are enabled!?
Anyway for a real bycicle routing I would prefer Oruxmaps (oruxmaps.com) together with BRouter (Playstore; download of specific elevation data from within the app) and maps from openandromaps.org. The B in BRouter stands for bycicle and considers slope and slope, and this example is even 7 km shorter. All is free as Navigator can be. ;-)