I have some Ilford XP2 negatives developed at a chemist in summer 2000. There are faint transparent crescent shaped marks on the film, irregularly spaced, all about the same size and all facing the same way. They are in different places in different frames and only barely visible. It looks like they are many or all the frames in this roll of film.
The same camera with a different roll of the same brand of film, scanned on the same equipment today, just before this set of negatives, looks fine.