I currently have a Epson SP 9890 and Epson SP 3880 (plus a little Epson 4020) I use your Vivid Magenta in. I have notice this for about the past 6 months of order this VM ink. In all three machines it always seems that it clogs bad on VM, usually something along the line of a nozzle check and the VM is completely missing or just no where near where it needs to be so it is printing nicely. All the other Conecolors work great I dont have clogging issues at all, some notches here and there are missing (typical Epson printer head) but thats it. I wanted to know if this has been an issue for you or anyone else. I print a lot with all three machines, I definitely know its not from ink settling.
Any information or a possible fix would be awesome.