Hello there,
First of all I feel your pain; tasks running overnight are an essential tool and to have that quiet space invaded is nothing short of criminal. A machine rebooting mid-meeting or mid-presentation is equally ridiculous and how that came to be approved and implemented we shall never know.
Hopefully the resolution should lie in the Windows Update > Advanced Options space.
On my Windows version I see:
This should be On as it is now, but it can mysteriously change itself to Off for some reason.
Worth checking the Active Hours settings - change these from Automatically to Manually, then define a large part of your day to being off limits:
Double-check anything to do with updating and rebooting.
Then, I'm afraid, it's a bit of a wait and see if that cures the issue.