I think the idea that there should be hyperspace out of the window is taking things a little too literally. Although there's nothing to explicitly say so, time could have passed between Vader's scene and the next - and if it didn't, maybe the Falcon only made a short (in duration) jump.

If you do fix it, the next space shot (again with no explicit passage of time) of the Falcon is in normal space, so the shot out of the window would have to show the Falcon coming out of hyperspace...

DE