I’m not familiar with the Fast Startup Feature. Is that a windows 10 option, VR, or AH3?
What 1stpar3 said, Windows. It's like Hibernation with the exception that it only saves your settings for the next boot, no matter if they're corrupted or not. A temporary fix is to press Shift when clicking Shutdown, a more permanent cure is to disable Fast Startup. "More" because Windows may re-enable it at some update.
You'll find it in Power Management (right click the Win icon down left)>Additional Settings>Choose what the Power Button does>Currently unavailable settings.
There's much more Power Management related settings which you should be aware of for best performance, they've been addressed in the Hardware and Software or Technical Support sections during the last year or so.