Maybe you should try the tried and true method that Grandpa swore by. A good whomp on the side.
It does sound like magnetic interference for sure. Could just be a defective set though. I would just try and shield the side of the tv with something and see if that stops the interference. If the disturbance doesn't move at all I would say it's the set. In my experience, any kind of magnetic disturbance will normally shift around a little bit--depending on the nature of the interference at any given time.
But if it were me, I'd want to talk to the people I bought it from before I made any decisions. I would expect that they would have a professional you could talk to on site. And you might be able to talk them into repairing it in your home or at least pick it up for you since it is a high dollar item.