This:
Sorry to say but those NVGs look very much like binoculars, so it stands to reason that what you would see looking through them would look like what you see when looking through binoculars = not a single circle but two circles pushed into one another. And that video you posted - I'm pretty sure the camera was looking through one tube only, so of course you would get one perfect circle, but I do not think that is what the human eye would see.