I think FOC (Post #4) is onto something, in that there are certain diagnostic features in your negatives (besides the obvious problem areas) that suggest the film may be touching in places. I've had this same problem on a couple occasions using the 120 Hewes stainless steel reels made for the Jobo 1500 series tanks. I didn't much care for the Jobo plastic reels, so I bought a couple Hewes reels (in 135 and 120) to see how they performed by comparison. I've since gone back to the Jobo plastic reels because, although annoying to load, they seem to produce more consistent results. The problem I found with the Hewes reels (especially the 120 version) is that the radial arms that extend from the central core across the spiral rails tend to kink the film whenever the film crosses those arms. The kinks, if bad enough, can cause the film to get dislodged and touch the film in the next outer track. Getting the leading edge of the film correctly positioned in the clip is also crucially important, because if the alignment is off by only a couple degrees, the film has to eventually kink (usually multiple times) in order for the film to be able to spiral onto the reel.
In the case of your negatives, the most important diagnostic features are the fact that the anomalies are vertical (parallel to the core of the reel), which is consistent with the idea that film from an inner track is making contact with film on the next outer track. There are also the half-moon spots on the the film that FOC pointed out, which I know from experience are what happen when the film gets kinked where it runs across one of the aforementioned radial arms. The other thing is that the anomaly is strongest nearer the inside of the reel (i.e., nearer the end of the film strip, which gets loaded first) and gradually fades/attenuates as you move toward the outside of the reel (i.e., toward the beginning of the roll, which gets loaded last). That said, I think it's also possible, as others have suggested above, that this problem is being exacerbated by a second problem: slow filling and dumping of chemicals (which is common to stainless steel tanks).
As suggestions, the first thing I'd try doing is the easiest thing: Add a five-minute water pre-soak (at developing temperature) to your C-41 routine. If the problem you saw above was due to film contact, a pre-soak may help the developer penetrate between the two pieces of film just enough to provide adequate development in the troublesome areas. If the problem is, instead, inadequate chemical flow (which in C-41 primarily boils down to a surface tension problem combined with the short, 3:15 development time), the pre-soak will help the developer penetrate the emulsion of the entire film strip more quickly and evenly. (The "average" consensus on pre-soaking color film is that it has mostly negligible effects, and that other variations -- temperature, agitation, etc. -- probably have as much, if not more, impact on the quality of the final product.) This is a sensible thing to try first because it allows you to continue using your existing equipment.
If that doesn't work, my second suggestion would be to use a plastic reel and plastic tank if you have access to them. This should help you avoid both problems all together. The only problem with a plastic tank in this specific application is that they're usually less dense than the stainless steel tanks, so it may be more difficult for you to keep the tank immersed in your water bath. Placing something heavy on top of the tank while it's in the water bath will help keep it from floating or rolling over.
Please share your results if/when you get them. Good luck.
