This happened when I pressed shutdown in start menu, then BSOD
Edit: I used NTVDM within that ros session before (start Prince Of Persia 2 - The shadow and the flame). Prince will crash (minor issue).
After that, shut down Windows via startMenu.
over 90% possibility to crash csrss then + said assertion + BSOD
I also found out, that this is a regression.
Guilty revision is r69554.
RegTesting was very hard though, because you need multiple testing cycles before you can be sure...