I can’t find any workaround for this. Most of my projects are based on projects from older versions of Cubase, and I thought that might be a cause, but it happens with a brand new C8 template, with no audio and just some Waves and UAD plugs loaded.
This is making it impractical for me to start using C8 64bit - I was actually quite happy with C8 32 bit but since going to Yosemite I have the black windows when I close a plug-in (see other thread here)
After many months of sticking with the old OS, I thought it would be safe to upgrade. WRONG.
Too many problems with Cubase on Mac at the moment.