Macbook Air (2012) says "Not Charging" when magsafe2 first plugged in but then starts charging after a few seconds. Is that normal?

Hi guys,

I just purchased my first Apple notebook, the Macbook Air 13", last week and needless to say its a wonderful machine. However I've noticed that when I plug in the magsafe2 plug to charge the Air, the text next to battery icon says "Not Charging" for a few seconds (ranges from 1 to 3 seconds) before it disappears and the battery starts charging (the thunderbolt sign comes on). Seeing as this is my first Apple notebook I am unsure as to whether or not this behaviour is normal. I've searched the forums but have only been able to find one other case (w/o a solution).

Thanks,
Dave