Hi all,

I occasionally have annoying issued with exposures with my Chamonix as in this frame:

This is a negative scan with an Arcus 1200. I am not good at scanning negatives but I hope it serves the purpose.

Details: Cham. 45N-1, f9/360mm Apo-Ronar, HP5+ EI400, D76 1+1 9'30" rotation. Jobo CPE2, Multitank 2553, frameholder is the one with the wings to clip in after loading. The tank was filled with 560ml. There were six frames in the holder two of them have these stripes. The other one is the same scene but taken with a f5.6/150mm Sironar-N. The stripes on this are less obvious. I don't know where these two frames were loaded but it is very likely that they were in opposite positions in the frameholder.
What is obvious for me is, that the stripes are very regular. So to me issues with pouring in or out the developer seem very unlikely.

Has anybody seen something like this and can explain it to me?
I always make to exposures of the same scene. So I can repeat the development. If this is an issue in the process I'd much like to know how to avoid it.