Bug: Unable to correctly attach source containing parents of undefined gender

Anne986

I am unable to attach this source which contains parents of undefined gender correctly to the couple in the family tree: https://www.familysearch.org/search/linker?ark=/ark:/61903/1:1:6ZBP-9QC1&id=KLT9-C68

Áine Ní Donnghaile

The record is already attached to the parents. All I did was change the focus person to show that it is attached: