@yumian is right, there's a missed opportunity.
The author's intent was to simply show how two-faced the "mob of nobles/other people" who simply just ostracized/feared her for her looking similar to the Spirit King of Darkness. And the author also intended to show that even if they started being nice to her due to her skin color change, she wouldn't simply trust their new attitudes. She even says that it doesn't erase all the bad things she's been forced to go through.
@KitsuVonKraft
Due to backlash from readers due to a certain chapter where she gets the blessing from the Spirit King of Light. The people who were responsible for publishing it, edited it so that she have dark skin again to avoid it, and altered text to ignore it. The main problem was, as I mentioned before, it was simply to show how two-faced the mob are when it comes to this. She was supposed to go through some bits where she's not trusting other people's sudden change in attitude. In the novel at least, she mentions that all the new "kindness" she's receiving feels more like malice to her.
Them before: (MC with dark skin and black hair) OMG she's the one with the Spirit King of Darkness! She might destroy the world! But if we do anything she might destroy us first!
Them now: (MC with her supposed to be original skin color + black hair) OMG, she looks so beautiful and almost like a foreign beauty! What? She has the Spirit King of Darkness? Didn't she also get the blessing from the Spirit King of Light? We should get closer to her~
It was a big missed opportunity to show the hypocrisy of others. Her parents too, particularly her mother who basically said "You don't look as frightening like before" Like what sort of parent says that to their young daughter who didn't asked to be born like that? And her father who was so damn wishy-washy about the situation. It was supposed to show that her siblings were the ones with no prejudice and accepted her as she is, when compared to the parents who assumed that since she's born that way and she has the Spirit King of Darkness, she's automatically a person to be feared and hope she doesn't destroy the world like the guy from the legends. I mean the old man butler is a better fatherly figure than the actual father.