Lag when continuously clicking and looking around at the same time (NOT fps lag).

Here's a video that I found which perfectly shows the bug : https://www.youtube.com/watch?v=d3YsGXWNjHg

So, the bug is getting lag spikes when clicking. Now, the thing is, I don't fps freeze. I freeze and cannot look around for about 1 second, but everything in the game is moving perfectly during that second. It also happens with the keyboard which makes me walk for about an extra second when i'm not pressing the W button. I have noticed that it happens in more intensive areas, but remember, it's not fps lag.