Please try following:
1. start basecamp
2. switch to profile "Mountain bike"
3. choose "New route"
4. create route from several points, then press "Esc" to stop creating the route
5. choose "Insert"
6. find the last point of the route you have made before, click on it
7. now you can add next points
8. during this process try to press "Ctrl" key
Consistent behaviour should be that basecamp temporarily switches to "direct" profile in my opinion but basecamp doesn't work this way, he stays in "Mountain bike" profile. My opinion is that this is a mistake and illogical behaviour.
Am I right or not?
I sent this to Garmin support until now we exchanged six messages and I am still not sure if I communicate with a person or robot :-(
Best Regards
Ivan