Im guessing it's because of the lighting.
This new hair color is very far from option B hair color and a little closer to C hair color. I think he mixed the two colors of option B and C for this new Sophia hair. Or Possibly, the way you say there may be some lights or the sunlight in the room may be reflecting too much on Sophia's hair.Blonde is not finalized in the poll and
You will see the true color in night scenes.
besides there is more than enough lights by the mirror to make the hair look shiny (for us to mistake it as blonde) and there is more reflection of sunlight in the room too. View attachment 2310024