I have a Pentacon Six 120 film camera and I am suddenly experiencing some kind of strange light leak on my films. Below, I have added a scan of the first three exposures on a roll and as you can see, at the beginning og the film, even the space between the exposures is affected. The vertical position of the mark is always the same, but it moves left and right relative to the actual exposures. On this particular roll, the streaks seem to move further left into the actual exposure for each frame, but on other rolls, they jump back and forth. On this roll, all exposures were affected, but I have also shot rolls where only some of the exposures have marks on them, and some rolls in between without any issues at all.
All films, with which I have had the problem are from the same brand (Rollei), but I have had issues with both RPX 100 and RPX 400 films and have shot many films from the same stock without issues, so I doubt that it is something wrong with the films. I am doing pretty straight forward stand development in a Jobo tank and have not changed anything to the way I have been developing films for years. Yesterday, I developed two rolls together and I had only marks on one of them.
Has anyone of you an idea what might be causing this?
All films, with which I have had the problem are from the same brand (Rollei), but I have had issues with both RPX 100 and RPX 400 films and have shot many films from the same stock without issues, so I doubt that it is something wrong with the films. I am doing pretty straight forward stand development in a Jobo tank and have not changed anything to the way I have been developing films for years. Yesterday, I developed two rolls together and I had only marks on one of them.
Has anyone of you an idea what might be causing this?

