> If Windows says "restart" that should always mean a full reboot as far as I know.

That is what i expected but it doesn't seem to work that way and i had issues myself with it with other things, like e.g. some older games use the system timer (which is reset at full shutdown) for their animations but if the timer is a large number the animations and movement might break. This wasn't much of an issue back when most PCs were shut down every day as it would reset the timer, but nowadays the timer state persists after reboots - it was what actually prompted me to figure out how to reboot the PC from the command line as that does a full reboot.

It might be a bug that persisted for a long time or some intentional feature, but either way it is something i've experienced on my PCs and for that reason i have a small shortcut that calls 'shutdown' with the parameters for a full reboot.