She should be considered “mixed” at best. Her Cape Verdean half is actually white.
Cape Verde was created as a penal colony for Portugal to exile their Portuguese misfits and prisoners they didn’t want anymore.
Cape Verde was also a slave port for African slaves, and the Portuguese colonized those Africans through marriage. That’s why the black Cape Verdeans tend to look racially ambiguous.
Amber’s mom is a white woman who descended from a Portuguese family located in Cape Verde, not the Africans there.