That's really interesting. Do you think it could be related to the effect of map projection biases? Is that a thing dates far enough back to affect settlement decisions?
Antarctica was not well bounded on maps until the Wilkes expedition and others in the 1830's.
However, the Polynesians were not cold weather people, and the subantarctic islands are extremely remote.
It was hard enough as it was for the Polynesians to settle New Zealand, I can't imagine them settling any further south.