You can go into open street maps editor and see if that section is marked as suitable for bicycles and have a look at the surface type, or if you would like. If you could send me the location I could take a look at it for you.

If I remember correctly, Richard updates the map data for this website once a month so after the change is made, it might take a while before you will be able to route along that section.

This is the path in OpenStreetMap:

https://www.openstreetmap.org/way/140174352

It’s currently marked as a compacted surface, grade3 tracktype (“an unpaved track”), and bad ‘smoothness’. Consequently c.t won’t route over it in paved mode.

If it’s genuinely paved then you can change that in OSM and c.t will pick it up at the next routing update.

(Note that c.t’s routing option is “paved” and not “road bike” – i.e. it will never route over any unpaved section in that mode.)

Hmmm, not sure what to say/do then. It is rough but it's not long and nor is it really unsuitable for (any) bikes. I just hate to think that the route offered when 'paved' is selected, is really NOT the right route for the sake of such a short section of, ultimately, cycleable terrain.

That’s the way the routing algorithm works I’m afraid, but don’t forget you can always switch modes between two via points – so if you’ve planned a paved journey but want to use another section for a short distance, put a via point on either side, and then at the first one, select ‘Go any way to next point’.