I've seen that on some units when cold, it's a problem with signal timing, and there's a fix in the next coming software update. As a workaround, let the camera warm up fully, and if needed you can partially tape up the fan if it's cold outside. You don't have to worry about the camera overheating, as long as the case stays below 50C you're fine, and it has a thermal shutdown if it for some reason gets too hot.
Were you using the camera in cold weather?
David