Mid run changes in color is a problem, color changes from week to week are usually lack of calibration. I looked at what you posted (err glanced) it does seem like Magenta might be a tad heavy in the highlight area's. Have you tried just changing out the IU for Magenta? Course remember... just cuz magenta show's up may NOT be the problem... it might be the only color that is working properly. but... by looking at what you posted it does look like cyan is being reproduced properly. Weird as I didn't see a Yellow gradiant.
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