exhaust fan New pc fans question

[Romee2]

So I just installed new fans for my pc. And I seen that my rear exhaust fan moves like this. I zoomed in and slowed down the video for context. If you look at the outer edges of the fans you can see what I’m worried about. I wonder if that motion is okay. My friend who builds and sells pcs for a living said everything is fine. And by the way the fan is a InWin Neptune AN-140

 

[tkitch]

yes fans do that, you don't need to worry about it