I've found either a strange bug, or a flawed design part of the Free Company's rank promotions.
As long as any rank is given "Promotion Privileges", it can promote itself anywhere in the hierarchy outside of Leader position.
Rank 13

Prompting me if I'd like to promote myself to rank 2


Promoting myself on an alt from rank 13 to rank 2


It's silly, and I wouldn't have found it without just playing around with things, and its not likely you'd give a rank low enough to abuse it's promotion rights anyways, but it's there.