It's the sort of black line that is technically a light leak (from the shutter light seals and the light is shining on the camera and film gate from above), and often caused by storing the camera with the lens off over a period of time or even a short time in bright sunlight. It's frame 34 and there is no normal exposure on that piece of film anyway. I guess for the half blank exposed frame you put your finger in front of the lens if you don't have a strap. If you are new to rangefinders it's a mistake anybody can make, even those who say 'it's never happened (yet) to me'.