Thanks all for these. I developed 3 rolls of Portra 400 within about a day with the same camera/lens combo. Only one roll had the leak. I do remember having some trouble loading one of the rolls into the reel and having to take it out and try again 3 or 4 times, which is really strange for me, as I've loaded hundreds of 120 rolls without difficult. I don't know what happened or whether it was that roll that produced these strange rings. Most of the photos came out unexceptional. Here: