Not surprised. The Luo people have lived in and around east and northeast Africa forever.
I should have this ancestry research done for my mom. The Kikuyu people are said to have arrived in Kenya around 2000 years ago with the Bantu migration, but they intermixed with people who already lived there.
Those were the original East African people-Athi, Ngumba, Yaaku, etc the equivalent of Native Americans. They're are now extinct because of intermarriage and absorption by the Bantu speakers who came from West Africa.
It's a similar thing in southern Africa. The native KhoiSan have lived there for 150,000 years but are now a minority because of intermarriage. Nelson Mandela had KhoiSan blood.