Data point: have purchased tickets for family members when logged in as me, using my credit card, and I have not been traveling with the family member(s). These family members share my last name, but not my first. It has been some months since I attempted this.

Their PNRs sometimes fell out of my reservations if I was not also traveling on some itinerary that coincided with theirs and had them linked by AA.

I hope this requirement is just a glitch and not an "enhancement" of any kind.