That would put modern humans reaching Australia 15,000 years before they reached Europe - an absurd result.
It’s not absurd. There’s a difference between “any appearance” and “any lasting appearance”. Anatomically modern humans, like other varities of homo sapiens, were great roamers. But whether the initial explorers were followed by enough of their kind to establish a lasting population is not a given.
That’s sumthin I had never heard of before. Sounds like it’s a good time to go into archaeology, with so many mysteries to solve.