Thanks for the additional information. Did the printer sit unused for the month between semesters? Have the carts been agitated, and any power clean cycles been preformed? What paper(s) are you printing on? Are you using Epson's standard workflow/profiles, or do you make your own profiles? I suspect the new magenta cast you're experiencing is likely due to the new OS and driver update (though I don't know how/why it would only effect the ConeColor printer, and not the other two), but settled pigment from sitting unused may be a factor. If you agitate the carts and do a few power dean cycles, but the cast is still present, I would be happy to make you a few free custom profiles if you don't have the equipment to make your own profiles.
Please let me know.