Update on the issue:
Yesterday I had the chance to sit down a couple of hours with a new project. It crashed during audio track recording, just one track.
I will uninstall and fiddle with the gfx drivers tonight. After I re-installed the iLok drivers it’s harder to trigger the crash though.
I could go back to 10.5.10 again but I really wan’t to solve this issue and find the actual cause.
I am in touch with AMD support about it at the moment. They have me jumping through hoops uninstalling and reinstalling the latest drivers, the older drivers etc. All the stuff I have tried already. I don’t know what they will suggest when I tell them none of it has worked. It’s got to the point where I can’t use Cubase at all though because I know at some point in the session it is going to crash.