Cross Calais: How Can One Feed Hold So Much Ink?

[lectraplayer]

This one has me stumped... I'm trying to change the color written by this pen, a Cross Calais cartridge pen, and it seems like the feed holds more ink than a cart or something. It also seems to have a backup supply to use after flushing. Normally, for most of my other pens, I can change the cartridge and maybe write half a page to a page before the color transitions fully if I'm sloppy and don't flush, but not this one. I've flushed this one several times after using yellow ink for a few weeks, and put a blue cartridge in behind it. I use it a bit, writing several pages, and the ink remains yellow, though there are streaks of black when I first start writing if I haven't in the last few minutes. (the ink I used before the yellow, haven't seen this phenomenon in any other pen). I flush it out again until the water runs clear through it, stick the blue cartridge back in and it writes yellow. I use it for several pages, and it never changes. This has already been repeated several times. Has anyone else run into this before?

Edited January 17, 2019 by lectraplayer

[JonB55198]

I would recommend disassembling the pen and cleaning it. Pull the nib and feed out and give them a good soak in water. Make sure you flush the now-empty section in case there is residue in there.