I am sorry, i misread the "ink pattern" as the nozzle check pattern. Can you post/link to a picture of the problem you are having.
If the ink separation page prints fine then it indicates the problem is with the profile, although without measuring the ink separation image before and after having the problem you can't really be sure.
Do the lines in the shadows run parallel to the direction the print head travels? If you create a smooth gradient from 50%K-100%K at a diagonal across the page does the solarization show up there too? You could even use the QTR bulls eye targets to see if you get hard jumps with one profile or another.
I created two 1/2"x4" opposing smooth gray ramps/gradients from 0-100 with the gradient tool in photoshop and include it with any new profile—either ones that are supplied or custom ones i create. It will make any problems in the profile with the overlaps and linearization painfully obvious.