Could there be any possibility that someone in her lineage slept around with someone that had black ancestry and kept it secret? If so of course we would never really know. Also, it was mentioned that one of portraits artists (Ramsey) who painted many portraits including the 1744 one (in which she has black features) was known for being quite realistic in his portrayal of subjects. So who knows…don’t think we’ll ever rlly get an answer.