The mathematical bias was the fact that dark skin has less illumination range, therefore less information to separate dark skinned faces. The bias was not such that a darker skinned person would be confused with a different toned person, it would have issues telling the difference between people with the same darker skin tone and similar facial shapes.

The bias will also have biased consequences, like for 1 dark skin criminal you search for you will find more suspects with a much higher probability or score then a light skin person, this would mean more arrests/interrogations.

I would also not blame the math but the implementation aka the coding/modeling of the problem.

which has been corrected.