I don't think the reddit post you got that from is correct. Looking at her grandmother I think she has a small percentage of white. If she is 80% black (lowball estimate I think) that alone would make Kamala 20%, let alone her grandfather who appears much whiter but still probably a mix. If he is indeed mixed that is going to push that percentage up. Assuming by 'Jamaican' you really mean black. She is 50% Jamaican. Grandma could certainly pass for 100% African. https://jamaicans.com/10-things-to-know-about-the-town-kamala-harris-jamaican-descendants-are-from/

I don't think the reddit post you got that from is correct. Looking at her grandmother I think she has a small percentage of white. If she is 80% black (lowball estimate I think) that alone would make Kamala 20%, let alone her grandfather who appears much whiter but still probably a mix. If he is indeed mixed that is going to push that percentage up. Assuming by 'Jamaican' you really mean black. She is 50% Jamaican.