Faint clicking noise when pressing the ZL button on the Nintendo Switch Pro Controller?

I recently bought a Pro Controller for the Switch and when I press the ZL button I hear a clicking noise (sometimes really rarely and only in certain places). Is that completely normal or what is it?

I don't know my way around that well, but do the other keys sound like that too?

But only one is really rare but a bit strange

ZR and ZL should click normally, yes

Thanks, but it's more of a higher pitch. Not that normal lower

As Pauli said, this should be normal. Maybe contact Nintendo

Then that's normal. If you are still skeptical, send me a short video of it