SB has been informed of the issue the OP stated. They were informed over a year and a version ago. And nothing. What is he supposed to do?
There is nothing on his system that is holding up/preventing Cubase from terminating - it’s not just him. It’s everybody else:
Aren’t you in that thread?
Opto > try “run as admin” option - that should take care of the shutdown problem.
Cheers.