Wow, what bummer, just looked at the 120 TX and it has lines too, but they're super consistent on it. Two lines of the same size and consistency running down the entire length of the film on both sides just in from the edge. Never had the likes of it. But I assume it's all related.
I would say light somehow, leaking where I'm loading or in the tanks, reflecting of the SS reels and exposing the film. That'd make sense for it popping up sporadically like on the TMY, but the TX is really consistent. And I'm talking over 13 rolls.
My retouch quota for the week just went out the window...
As a note, not that I think it matters, the TX was in HC-110. Not rodinal. With that, all of this film TMY+Rodinal, and TX+HC-110, at my temps, had short dev times. Btwn 5:30 and 6:30. The bottom end of safe times...but I'm not sure how it'd do this.