I owned both, and I don't recall ever having that problem. Maybe with wide lenses or subjects at infinity, but if I was shooting Polaroid on the S2a with the Type II bellows, it was more likely with a longer lens for some tabletop/macro/portrait use, so it's possible that I never encountered that situation. I've sold the camera, so I can't test it out, but looking at my photos of the bellows, there are two screws under the front standard, and I think you could use those to set the standard back, if the rails were bumping against the Polaroid back.