System is going to sleep
Having the same problem - this is my second replacement new machine. I think it's a design fault rather than a machine fault...will try AppleCare/Genius but they've closed the biggest store and so hard to get anyone to talk to. It's crap, basically. Not impressed with Apple - and I've been using their machines for 5 years!
And Dan - it's the SAME problem. Tilting is the only thing that fixes it. It went away for a while with my old machine, but as this machine is basically a clone of that one, obviously my fixes didn't last for some reason.
Is this a good question?