Seals all look fine. As do the bumpers. Im lost tbh. Only thing I can think of is a bit of packing foam got caught in the bottom of the canister and got slowly broken down as I rolled the film through ?
From your pics it looks like it's not crumbles but rather shavings, as if something sharp had been shaving at the take up spool (it's the only white thing in there, or maybe there's some other cogs inside.. doubt they'd be plastic though)..
Seals all look fine. As do the bumpers. Im lost tbh. Only thing I can think of is a bit of packing foam got caught in the bottom of the canister and got slowly broken down as I rolled the film through ?