It actually shows a deeper yellow in the preview with 2 yellows instead of one, and that's the color I wanted, but I can't apply it because the dye cannot be of the same colour.

Here's a screen of the difference in colour:
Why can't I apply it when there's obviously a difference in colour in the preview. Anet: let me add 2 dyes of the same colour if I want please.
There's nothing that can be done about it atm, so I'm not really looking for an answer. I only hope to see a fix or something.
PS: this is not the only armor with which this happens. I've seen it on more armor previews.