That's strange, I went to the raws to check this chapter out beforehand and her skin color after she was blessed...was still dark! But here it changed! Weird.
Anyway, this is such a bad change, and I'm not just talking about race here. I am not qualified to talk about that, there are others who can take care of that angle.
Fortunately, there are OTHER reasons why the skin color change was a bad choice!
1. The meta angle: This is a manga adaptation of a light novel. I haven't read the LN, so I don't know how the skin change was described over there, but the manga already has a disadvantage- the manga is in black and white. So either her skin was going to look muted, which would make it hard to tell anything changed, or poor Claudia was going to look like she had white powder layered all over her skin. It just looks bad either way.
2. In-universe angle: ...can you actually tell, in-story, that something changed? I mean, imagine being there, seeing a young girl's skin change from tan to...pale? Is that something that noticeable? Actually scratch that: I'd argue the people of that world would be even more frightened. She still has the "dreaded" black hair, and now her skin turned into a ghostly pale pigment. I dunno, I think the dumbasses of this world would be more uneasy!
Obvious solution: change her hair color from black to blonde (or part of her hair idk which). Would be more noticeable, would make her fit in with her family, and dark-skinned girls with blonde hair look cute anyway lol. Otherwise, don't bother with appearances, give her like a marking/tattoo or something.
