On a six or two lens camera, this defect will be on the top or bottom. When the white tab is not pulled straight, the negative and positive do not come together aligned. If you see this defect, open the film back,and remove and clean the film rollers immediately. Do to the misalignment, there is usually edge leakage of the film chemicals onto the film rollers. If you open the film back, and leave the film pack in place you will not lose any film. If you do remove the film pack, you will only lose the first sheet.