Digital BW, The Print

I'm printing in ABW mode on an Epson 2400 with Epson K3 inks.

My prints often have a very slight bluish color cast in the shadows; when I
stare at the print for a few minutes, the effect is enough to make them look
slightly hand-coloured. It's only noticeable on prints in which there's a
smooth gradient in the shadow tones (eg in a darkening sky, or around the
hairline in a portrait). Spectrometer readings show the effect as a dip in B*
of about 2 points at densities between 70% and 90% typically.

Has anyone else been bothered by this effect? I'm not sure if I'm expecting
too much from ABW; given that ABW uses standard settings for all papers
with a given media type, I'd expect some color shifts across papers, but I'm
surprised that it looks so bad. And I see it even on EEM too, albeit to a
lesser degree than on Entrada and Photo Rag.

--Daniel