I have heard of complaints of shadows going excessively blue on Ektar, and have seen it myself in some prints I have made but accepted it because the shots were on a sunny day and the blue skylight would be expected to cause some blue in the shadows. Add to that the fact that Ektar is a high saturation film, and this would cause the blue in the shadows to pop out just like everything else. That is my theory of why some users are reporting this. Someone correct me if there is a reason why this wouldn't be so.
The characteristic curves on Kodak's website show the yellow layer curve to be slightly higher in contrast than the magenta and cyan, so if anything this should be causing the shadows to go yellow. But I know of no one reporting that. Perhaps Kodak deliberately designed the film this way to help minimize the blue in shadows.