I was having surge problems with the hangers I was using at the time. I switched to semistand and high dilution and it solved it for me. I have used a jobo but didn't have any problems. Thinking about it more, the spots are light which means more density. I was wondering if, with that short of a developing time if some developer splashed during filling. That might add enough difference to cause it. If your tubes have enough volume I would recommend diluting developer 1:1 and try minimul agitation, and a presoak. Generally developing times shorter than 5 minutes are not recommended as it allowes uneven development. That might be the cause of the streaking. I now use pyrocat with Fp-4 and like what I get. I'm also thinking if it was dew it would be more overall. Then again I haven't had that problem . (yet)