I knew a girl who was colorblind in HS. She had consistent colors, but they were all subdued. The best way that we could figure to describe what she saw was that she saw the world as a "pastel" version of what we saw. She might see a shade of blue as a soft green, but she would always see that same blue as that same shade of green. There was consistency in her colorblindness.

I doubt that describes all, or even most colorblind people. But, certainly not all colorblind people have inconsistent colors.