Green dotted banding on Portra 160 negative

Greetings forum,

I need your help!

I just home processed a roll of Portra 160 with Cinestill C41 kit - Scanned the negs with Silverfast and saw this weird horizontal band of green dots on top of the image - there is some in the center as well. At first I thought digital noise but the dots are indeed on the neg.

I also processed a roll of Portra 400 the same day and it came out fine. Different Patterson tank though (should not be the issue but I'm at loss for explanations)

Seems to be a development problem, but could anyone help me and confirm what the heck has gone wrong?

Thanks a million!

Looks like a problem with backing paper on 120 film that was moist and/or hot during storage.

koraks said:

Looks like a problem with backing paper on 120 film that was moist and/or hot during storage.

Click to expand...

Thanks @koraks - Storage definitely has not been optimal.