@Marschel If you navigate offline, you indeed won't have live traffic information. That's not possible because there is no internet connection!
Now the internet goes down during the journey, the route and the maps are available offline, as long as I don't deviate from the previously calculated route everything is fine. Do I understand that correctly?
That's correct.
Now I deviate from the route, which triggers a recalculation. What happens then? Recalculation not possible, or does it use the offline maps and the offline route to navigate me to my points B and C. The moment it finds internet again, it is of course recalculated, but what does it do in the meantime?
It will no longer take live traffic information into account, but the route will be recalculated based on the offline maps. Once an internet connection is available again, live traffic information will be included in the recalculation.