Got this Fed 4 from Tony "angry troll" Gale. Shot my first roll and was super excited. However, got this strange line down some shots, and about 20 didn't come out! Boooooo!
diegoafernandez, z790406, kahlan, doubleagent19, scorpie, konbiw, nicolas_noir, mafiosa, atria007, funfun, walasiteodito, easilydistracted, weleasewoger72, tsingtao & rik041.
This maybe too late to help but If you don't have the lens cap on when you wind the film back then you can get these lines with the fed-4. That may have been your issue.