Like you know, it’s not still because somebody can’t reproduce it on it’s end that the issue doesn’t exist.
Like i describe it in an other comment, it’s happening only since last patch. And it’s an other randome thing. You may shut down you game 10x and nothing happens, but it happens from time to time, not each time you close it.
Then, yes, i imagine that you run easily the creation kit, the game, and whatever software on your end, but consider that no everybody has a machine like you own. Sorry.
Most players have let’s say more random machine they use on a daily base. 
It may also be a Steam problem here, i don’t know. Steam like we know all is a beast, and has also some troubles, and they’re still also try to introduce new features.
Seems there also some other users experiencing this issue lately, so i’m not alone.
And last, sure when this happen, i know how shut down a process by tasmanager, and also how reboot my own machine. I do it several time the day, i’m sure not all will.
Killing unneeding process before performing heavy taskes seems a healty routine to me anyway.