I’ve had that happen to me, too, and I think it’s lying to us. Windows doesn’t need to reboot, it needs to do some cleanup work and then reboot. Only it doesn’t tell us that.
The best part is when Windows tries to reboot, but the Dell laptop decides that it won’t have any of that and crashes, so you come back from your break you find yourself in the BIOS and the update didn’t install after all.
Dell, not even once.
You think that’s bad until a HP laptop deletes your boot entries because you’ve used an external drive to boot up once and it doesn’t provide you a way to add them back from within UEFI settings so you just have to manually navigate to the correct .efi file and then add the boot entries back from within OS but oh wait you need to come back to UEFI to put them into correct order.
Also applicable if you forgot to unlock DriveLock before going into UEFI.