It looks like the skyshard on the pedestal in Vvardenfell is always returned with TrackNextActivityForZoneStory or pin.m_PinTag.isZoneStory , pin:IsZoneStory() even though it has already been absorbed/completed.
To my knowledge TrackNextActivityForZoneStory returns nothing in any other zone when all zone stories are done.
"At a small shrine where the road forks."
internal id: 20953
It's that precise skyshard :