Yo Vilhelm, I need you to take a deep breath and take a look at something. It's about the impact of lighting in ARR's engine, specifically on hair.

Alpha first look: Video 1 - Character creation.

At about 3 minutes in, they are showing the different hair styles on a Miqo'te without changing the colour. The hair colour, as can be seen earlier in the video, is rather white. But those indoor lighting effects cause some incredible shading to the point that it is turning brown.

I think this is what we're seeing on your husbundo.