It's working if I disable all the log output options! If I enable that again the problem is back
I'm on Windows 10 1809 and C4D R20.059.
I removed all the materials to see if something would change, and reset the render options. I've attached a bug report from C4D and the original project.
I get crash when I drop a something in the node editor. If I create a new project and don't touch anything in the octane rendering settings the node editor works, but if I copy paste the settings from the buggy project then it crash again, even if I reset the settings.