That's the unrelated green-turtle issue. It's only relevant after the guest has actually started running instructions. I'm talking about before that point.
>>datafl+(OP)
I'm not aware of any turtles, that was just the first thing I found when trying to see if VirtualBox and Hyper-V were still a problematic combo.
Again, it was a few years ago, but we didn't solve the problem or identify an actual root cause. We stopped banging our heads against that particular wall and switched technologies.