I have this annoying issue with my two month old iPad.
To cut the long story short, I've filmed the issue with my webcam.
It is really hard (almost impossible) to reproduce the issue at a store, but sales representative has taken it to check if the device is ok.
Now they tell there is a problem with the charger brick and they'll replace it. After that I'll have to discharge the battery completely, recharge the iPad using new charger and the issue should be gone.
Did anyone experience anything of this kind?