It's a colour palette bug from several patches ago. I'd like someone to rebuild the whole thing and give custom CoAs to big dynasties, in honesty. Again, we need a gfx guru to at least consult with us on what to do.
To go into more depth on the CoA issue, there was a colour code that was forbidden around the time of SoA. The mod would not boot up until it was removed from the palette. What I had to do was replace that colour with a dummy colour, which apparently shifted every colour along the numbered list by one. The effect of this was that CoAs that are cut into halves, thirds or quarters (and thus have a distinct colour for each) often had colours that didn't match up, because their numbered colours were no longer aligned. A CoA that had red as part of its design continued to have red in one quarter, but ended up having black in another, for instance. The fix would effectively entail isolating where the offending code is and pulling it out. I do not know how to do this.