There was nothing to mix up. At first there was no cyan, then there was. And now there is.
Yes, I messed up because I missed the fact of, and the significance of, the black tape on the end of the toner cart. Which is still there on the yellow and magenta, with no effect on performance.
And it wasn't a 'toner dam' it was a bit of black tape on the end of the cartridge.
