the maps from Google Maps.
This has advantages: The map is always up-to-date.
It also has a downside: if roads are temporarily blocked, you can’t use these for planning a route.
At this time this can be the case with mountain passes.
While you can set waypoints, the route won’t be shown on the map.
Annoying, but not a big problem, as your navigation system will recalculate the route based on the route points that you enter.
In other words: the route line that you see in Tyre is a handy tool, but it’s not necessary for entering the route correctly into your navigation system.
You can also place a route point each just before the mountain pass and just after the mountain pass.
Then select the route point before the mountain pass and click on 'skip'.
then place a straight line to the next route point after the mountain pass.
In certain situations Tyre will automatically place a straight line.