They didn't mention at all how much downstream admixture there is.

It seems like this article is implying that the one of the 3 main genetic components of Europeans (WHG, ESH, EEF) should actually be split in 2; that the Western Hunter Gatherers is comprised of 2 distinctly different groups circa 14000 bc.

EEF's didn't move in for 8000 years (at least), ESH's were 11000 years away. Did these two groups mix or did they remain genetically distinct?