Odd manufacturing fault - Fomapan 100

There are two pairs of dark parallel lines across the corners of two adjacent frames & towards the centre of the second. (See phots below). I thought at first this must be some kind of light fogging, but it couldn't happen like that in a camera, or on the roll and my negative processing area is completely light-tight, and I don't wear a watch (I don't own one ).

As I took the negatives out to photograph then (I don't have a scanner here in Turkey) I noticed that in fact the dark lines corresponded with very slight creases in the film support, so the fogging is stress marks. This must have occurred during manufacture, as it would be impossible to crease film like that in a camera or during loading it into a developing tank.



The second photo shows the creases in the film, note how the reflections change.



I've sent the same details along with batch number etc to Foma.

Ian