QTR-Quadtone RIP

Hi, all!

For the past 6 months I've been using QTR on my Epson 1280 outfitted
with MIS UT2 and Eboni Black cartridges, and printing on Epson
Enhanced Matte paper and Premier Art Matte BW paper. 

Until now, all my prints came out great using any of the default QTR
curves I selected --i.e., "cool," "neutral," "sepia," or "carbon."
However, this past weekend when I replaced my empty UT2 cartridge with
a new and unused UT2 it was a different situation altogether: Every
one of my prints came out of the printer with blue-cyan tones no
matter which curve I selected!

I assumed that I had a defective cartridge, so I printed out MIS's
six-band "purge" file to check it out. Instead of QTR, I used the
default Epson driver via Photoshop. Each of the six ink bands looked
like they should --the warm ink bands were warm, the cool ink bands
were cool, and the neutral and Eboni ink bands were normal.  

Does anyone have any idea what the problem could be?