Screen glitch or just normal

[joshrock11]

I recently purchased an iPhone 3g from apple and sold my original 2g. I never noticed my old iphone doing this so I figured I would ask in the forum. Whenever I hit the sleep/power button or home button to wake the device the screen appears to hesitate and sometimes a grey line appears at the bottom for a split second before the LCD shows the slider page. Is this normal or a possible issue with the LCD?

 

[italiano40]

normal it happens on my ipod touch sometimes