Caused by the distance between the viewfinder and the lens
Parallax describes the difference between what is seen through the viewfinder of a rangefinder camera and what the lens records on film. This is caused by the separation between the viewfinder and the picture-taking lens and is most evident at close distances and is the reason that most rangefinder lenses cannot focus closer then 3 feet.
This means that rangefinder cameras aren’t fully what-you-see-is-what-you-get because you frame the image with the viewfinder, but the photo is taken with the lens which is typically a few inches below to the right. To combat this some cameras have built-in parallax compensation where gridlines in the viewfinder move to compensate for the amount of parallax. At close ranges, the frame lines in the viewfinder will shift toward the optical axis of the lens. Anything outside the frame lines will be cropped. With the Konica Auto S2 the area of the frame even contracts very slightly to match the narrowing of the picture angle as the distance between lens and film is increased.