The protohistoric Swat Valley "Indo-Aryans" might not be exactly what we think they are

I need some help interpreting these linear models of ancient and present-day South Asian populations. Overall, the Iron Age groups from the Swat Valley, or SPGT, look like rather obvious outliers. The relevant datasheet is available here.





The reason for this might be significant bidirectional gene flow and/or continuity between Central Asia and the northern parts of South Asia before