I was suggesting a light leak (likely very low level) after the film is in the developing tank, not one in camera. However, I see only the faintest hint of the bands in this version, and I can't be sure it wasn't in the scene (it doesn't run through the sky at the top). On that basis, I'm going to drop my suggestion of a developing tank leak, and gang up with the others to suggest it may be unevenness in you scanner's light source. Can you make an optical print of the negative? That'll tell you everything.