I hate to be the linguist/lawyer type, but this kind of language is a huge part of the problem with regard to the cryptid hominins.
Modern: "relating to the present or recent times as opposed to the remote past."
Human: "Of the genus Homo, of which Homo sapiens is the only extant human species."
Neanderthals were modern humans. Denisovans were modern humans. You and I are modern humans. If sasquatches, almas, almasties, yerens, etc are discovered and (most likely) decided are of the genus Homo, they will also be modern humans. All of these are different species. Thus, if Sykes is saying that Zana was "100% Homo sapien", that is the term he should have used.........but he didn't.
Why?
Where is the timeline break you refer to? I believe Sykes suggests that Zana's progeny emerged from Africa over 100,000 years ago.
That's it; I'm ordering "The Nature of the Beast" right now so I can quote properly.........