I am remembering that one of the Asian populations on my grandmother's DNA Tribes was called "Iban Borneo" (The other is from Naxi, China).
In re-researching Madagascar I see that:
Madagascar, Home of the original Blasians:
Madagascar. Home of the original Blasians: "Initial human settlement of
Madagascar occurred between 350 BCE and 550 CE by Austronesian
(Populations from Southeast Asia and Oceania) peoples arriving
on outrigger canoes from Borneo. These were joined around 1000 CE by
Bantu migrants crossing the Mozambique Channel"...."Recent DNA research
revealed that the genetic makeup of the average Malagasy person
constitutes an approximately equal blend of Austronesian and East
African genes, although the genetics of some communities show a
predominance of Austronesian or African origins or some Arab, Indian or
European ancestry. Austronesian origins are most predominant among
the Merina of the central highlands, who form the largest Malagasy
ethnic sub-group at approximately 26 percent of the population, while
certain communities among the coastal peoples (collectively called
côtiers) have relatively stronger African origins".
So it looks like some ancient Blasian DNA via Madagascar (Bantu + Indonesian or Polynesian, depending on the person) is in order.