Light leak? How old is your tank? I have an old Jobo that gives me similar artifacts. It has been retired. Never traced down the actual cause but a group on PN where I participated at the time narrowed it down to a pinhole light leak.
No light leak. I used the 2502 reel inside the 2521/3 tank. I've used this setup to process several rolls of BW film.
BTW, what is a "pinhole" light leak? Just curious.
This is an old Vericolor III film. It was loaded in a film back which I purchased. Then I rewound the film back to the spool and taped it. I used this old film just to test the chemicals.
I'm not sure if this is because of the old film, or from air bubble or anything else. The chemicals I used were all clear, no solid residues.