Disclaimer: Please note that this is my understanding of points that I remember ES and Aleph bringing up in homebrew at least months ago, and may not be accurate. On the other hand, what I am certain of is that this homebrew was brought up during a discussion of Asarnin specifically.
The thing is, on the now rare occasions a Yozi actually grows a new Third Circle, or has to replace one that's permakilled, it's possible, although less likely, for the new one to be promoted from the Second Circle and a new Second Circle formed, rather than having a new Third Circle coalesce out of nothing. The reason this is the less common version is that it's something like one in a thousand Second Circles that actually qualifies for such a promotion, which is enough that most of the Yozi don't have one.