Jay here, with the EM problem mentioned above (person leaning in).
My film canister may have sat a bit, once exposed, I think.
In these conditions, I wonder if a minute cassette felt leak could affect mainly the one frame facing the cassette slot, and, as in my case, and another frame under the first layer, but to a lesser degree?.
I need to inspect my respective frame numbers, and also check what film it was.
How often would you find a faulty cassette?
Other: could this be processing problem?