Isn’t her mother ‘half-black’? That would make her 1/4 black, or maybe even less. That’s why she had to get out of the UK... No tanning results in more ‘whiteness’ on her behalf.
Yes, her mother is, IIRC, a quadroon, which makes her even LESS “black”.
Maybe some stores say she’s half black not sure how much she is.
‘Dorito” Markles is your average black American citizen, of mixed up, mostly untraceable heritage.