This happens a few times during Empire Strikes Back. The picture seems to stretch.
That's down to the camera focus changing. You don't see it in every film so I assume it's down to the kind of lens/aperture being used - you can see it in Goldeneye when they're demonstrating the helicopter.
I'm not sure from a quick look at the clip whether it can be completely fixed - I suspect some part of the picture will always be stretching relative to the rest.
DE