Had to edit the entire post and its title, because I think I found the problem.
I found out that C10 changes the VST audio system by itself. I went to Studio > Studio Setup > VST Audio Systems, and noticed that it had changed by itself, very strange. This has happened twice now, but I will need to do some more testing to see if I get this with another audio interface. This has never happened in earlier Cubase versions however (currently the latest I have is Cubase 8.5)