As long as its not doing this i would not be to concerned. At the moment
this happens 2 out of 4 times when rendering & gives an Apple report as well as Archicad Crash report with GDL & open GL errors in the reports.
Hopefully GA is looking into the reports. No i have not got layers set as transparent as was suggested by GA:?:
But if yours gets to this point then im not all alone.