Windows event id 4802 and 4803 triggered at the sa

问题:

Event id 4803 (Dismissal of a screen saver) is triggered immediately after Event id 4802 (Invoking a screen saver). Note that screen saver is actually still on till user interaction is detected.

I am using windows 8.1. On windows 7 Event id 4803 is emitted correctly i.e. after screen saver turns off triggered by user interaction.

Why is Event id 4803 triggered right after 4802?

Update: I've been testing out the screen saver invoke/dismissal mechanism by windows 7 and it seems that if youtube is enabled same thing occurs.