Digital BW, The Print

On my second set of MIS VM cartridges for the 1280 I started having banding.
Did a couple of cleaning cycles, image improved. Then all kinds of
weirdness. Very blue image or missing detail, etc. I used a bit of windex
here and there :), nothing got better. Finally replaced the cartridges with
Epson OEM color inks. After a few cleaning cycles everything great again.
Nozzle check runs fine.

Also, the cleaning cycle is *much* shortened when the MIS cartridges are in
there, about 20 seconds vs. a minute or so with Epson inks installed.

My question is: is it possible that something went bad *inside* the MIS VM
cartridges?

Thanks,

Luke
Iowa City, IA