The Genetic Origin of the Indo-Europeans

[Jaska]

we now know the exact reason why anatolian languages were outliers among IE.

1) It is because they were spoken by populations rooted in the Progress cluster that was IEzed by the Ukraine neolithic folks. IE languages that are rooted in the original cluster ( represented in Yamnaya and CWC by the Dereivka cluster) are more "normal" IE languages. This in case the eastern route is the right one for anatolian languages.

2)In case of western route anatolian are divergent because they got massively influenced by the local ANF/CHG population of anatolian copper age.

Anatolian is not just divergent, it also contains some archaic features vs. innovations in the Core PIE (Alvin Kloekhorst has presented these arguments in his studies). Therefore the difference cannot be explained from Core PIE by assuming some "learning errors" made by foreign speakers, if that was your idea. Proto-Indo-Anatolian was real and clearly older than Core PIE.