Holding my S3 makes a "crack" noise

First, my phone works fine.... this is not a big deal but it bothers me a lot.

A couple of weeks ago I noticed when I was holding my S3, lightly squeezing the edges or the back cover, the phone was making a sound like it's not well assembled.. like it is loosen... (like a low "crick" or "crack" noise inside or something)... I don't know how to explain it better..

Anyway I found out that if the battery is removed, squeezing the phone sounds just perfect, very well assembled with nothin loosen inside (no "crack" noises)... So its obviously the battery that seems to be causing this...

Is this just happening with me or its a ordinary problem?? Is there something that I can do to stop this?

thanks!