I got a new ipad 4 lte. when i press it on the screen (in the middle and a bit underthe front camera eye) I hear a sound like a bubble popping. As if there is an airgap under the screen. The sound is like click/clack. (The pressure is the normal pick up pressure). Is that normal? Should i return it back. In that case do they replace it bya new one or they give you a refurbished ipad? Thank you in advance.