Hi @FennecusZerda and thanks a lot for your message! Sorry for replying late, this month is very busy at work and I don’t find a lot of time to come around here at the moment 
It would be great if you could double-check the Norwegian EuroVelo routes on OSM and see if there are any discrepancies with the official tracks. You could use the Knooppuntnet monitor tool that we have been discussing here and in other threads (see for instance this one): Knooppuntnet monitor - OpenStreetMap Wiki
Feel free to reach out to me if you find out some major discrepancies, and I could get in touch with Henrik to discuss it with your help!