Digital BW, The Print

I bought a new r2400 recently and on the advice of a friend, purchased a replacement set of 
MIS K4 inks for when the epson carts run out.  It is for B/W only work.

Well I ran out today, so I plugged in the two k4 carts for the empties (LLK and LM).  Imagine 
my suprise when the first two prints out of the printer had big magenta splotches on them.

Not happy.  So I took the cart out, reset it and now its printing ABW with a massive magenta 
cast.  

Any ideas on what is going on here?

Luckily I was printing on epson prem glossy as a test print instead of wasting my good 
Museo/Innova paper.