When Windows wakes itself up to do things like that, it wakes itself to a different sleep level where it can still do things but the machine isn’t visibly on. That’s the whole point of S0 sleep. If it’s fully waking itself up to do things, then either S0 sleep is disabled or there’s a firmware bug affecting the motherboard that means certain actions during S0 sleep will exit sleep (which is more common than it should be).
Or they’re using S0 sleep and the computer is waking itself up to update
When Windows wakes itself up to do things like that, it wakes itself to a different sleep level where it can still do things but the machine isn’t visibly on. That’s the whole point of S0 sleep. If it’s fully waking itself up to do things, then either S0 sleep is disabled or there’s a firmware bug affecting the motherboard that means certain actions during S0 sleep will exit sleep (which is more common than it should be).