Hi Paul,
Apologies in advance for not having much on this one,
I was working yesterday in a project that I was opening on my octane machine for the first time (ie first time converted, previously the project was opened on non-octane machines only).
I had just finished swapping/improving all the materials, adding some decals to screens in the scene etc and I did a save all as defaults. I then I got a JIT error: no hard crash, Revit and Octane continued to work without issue for the rest of the session with 1 minor exception, a little later on I got a error relating to not being able to save to a null?
I did copy the JIT error and was going to put it into an email to you but I was under the pump and copied an octane material to clipboard so I could paste & tweak in standalone and lost the JIT which was still living in the clipboard!
if I can reproduce the error I'll send the JIT...
EDIT: p.s. We are using 2015 on this project...