Lumia 630 Navigation buttons squeak/buzz

[WPCentral Question]

Got the lumia 630 yesterday, by the time I got home, noticed that all three navigation buttons at the bottom kind of squeak/buzz with every tap. Didn't notice it in the store with the sales rep. Should I be concerned that this is a big problem? The buttons function, they just squeak with every tap. I even wonder if it may be the tiny vibrations of the buttons against the screen protector film, is that possible? Is it just the sound of the vibration against the screen protector? Please advise, if this sounds like a defect, I want to replace it immediately.