I've followed this thread for a long time and used the film a handful if times. I'm convinces, reading individual reports and taking this thread as a whole that the issue is to do with light piping and not bad film.
Everyone is aware of the issue but not recognising that it may be the only cause of the problem. If the problem is worse near the leader and gets better throughout the film this sounds like classic light piping.
I don't think this film can be handled like normal film. I think you need to treat it like HEI and load I'm complete darkness. I also think it should be stored in black canisters, which my film came in but I'd sounds like others haven't.
A real test would be to look at results from 120 film where the backing paper should stop the light piping. Has anyone experienced this problem with 120 film?