It's a possibility suggested by the authors.
Some context:
In addition, only one maternal lineage (mtDNA) lasts longer than a single generation.
Out of 104 individuals, 10 parent-offspring pairs were found, 6 of which were mother-offspring pairs. In 9 out of 10 of those pairs, the offspring was a male. Males with relatives buried nearby were mostly higher status and all from the same lineage.
So out of 46 adult females, only 4 had offspring among the burials. 3 out of 4 of these mothers were high status. Among the 42 women for whom no offspring were discovered, 3 were high status females of non-local origin. While it's worthwhile to note the observation, I personally don’t find it particularly remarkable, considering the number of individuals for whom no offspring, no spouse, and/or no parents were found, and that it appears that any adult female offspring would have been buried elsewhere.
EDIT: It's 6 mother-offspring pairs but only 4 mothers because 1 mother had 3 sons.