Sounds like the windows 10 'innovation' called fast startup. Some genius decided instead of shutting down, let's just log the user out and put the OS into standby... That'll save a lot of boot time!
It's universally hated by IT and made redundant by SSDs
Also it really fucks with some peripherals. I even had a motherboard with RGB lights (don't judge me, it was actually cheaper than the "normie" version I originally wanted) that didn't turn off the lights and the fans because of this shitty feature. I never got around to investigating who was doing things wrong between Microsoft and the manufacturer in this case though, I just got into the habit of holding shift while clicking the shutdown button.