Hi Jereon - I am getting this sometimes too - although I find all ArchiCAD windows display blank from time to time, not just Octane windows. My theory is that it is an ArchiCAD GUI issue with my Windows display adapter. It looks like ArchiCAD is issuing the window "paint" prior to Windows having displayed the window. I have tried to re-arounds, like re-painting the Setup window after it is displayed, but that has not helped. It will be interesting to see if ArchiCAD 17 rectifies this issue.Seems like random.
Paul