Quick question on unwighted-unifrac-significane output


I have obtained "core-metrics-results/unweighted-unifrac-subject-station-significance.qzv" file by following the instructions in "Moving Pictures".
My question is, I have three samples per each stations (n =3), but in the X axis in below image, which is one of seven graphs that I obtained, it appears with different replication numbers, for example, n=9 in St. 2.

Is something wrong in my metadata? metadata.tsv (292 Bytes)

Looking forward for help. Thanks!

This question was already addressed several times on the forum, so I will provide you with the link to the similar topic with explanation.