Mechanical sound from the camera

I have got my M2-mini from china (U model), and in general I am very happy with it (high value/money ratio).
I have OS 4.5.3.2.A and everything work fine except a sound from the device camera.
when I change the camera modes or when I switch back to the camera from the gallery, I hear a sound like mechanical clicks (2 clicks - one after another).
It is not a sound from the speaker but comes from the device itself.

Any Idea what can be the cause for such a sound?

thanks for the answer.
Does anyone hear that sound from its M2-mini device?

Thanks for your reply Zafeiria.
So what did you do with it? is it hardware or software issue? have you solved it?

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