Fast startup combines hibernation with shutdown and is designed to allow your computer to boost faster, but if you don't like it, you can disable it.

You can still use the Sleep mode instead, so hibernation is not really necessary. Thankfully, hibernate is usually disabled by default, but if your PC is different for some reason, you can disable it.

How to disable ACPI wake alarm 1] Adjust Hibernate Settings The Hibernate after Sleep feature transitions Windows PCs from a sleep state to hibernation after a set duration.