Not responding when power lead is plugged in

When I plug the power lead in the phone it doesn't respond until you press the power button 1nce very quickly not holding it down like your switching it on and then it will display the battery charging icon.

It does the same when the phone has power in the battery when the phone is turned off plug it in and nothing until you until you press the power button 1nce very quickly not holding it down like your switching it on and then it will boot up apple logo etc.

I know this isn't a bad fault but it's very annoying, any advice appreciated.