Well Duh!
If you go to Madagascar there are lots of people who look Polynesian. A good deal of the cabin crew on Air Madagascar were (at one time) of pretty obvious Polynesian decent.
They spread a lot further west than the not that isolated Andaman Islands, down through the Seychelles, Maldives and eventually ended up in Madagascar. Some probably went to Africa but AFAIK there weren't many successful settlements there.
I'm not surprised by the spead of these peoples. Their navigation skills in simple outrigger canoes are there for all to see in many parts of the world where the fishermen go beyond the horizon and well out of sight of land on a daily basis. Most eschew the use of any form of navigational aid and that includes a compass.