Perhaps, but it depends on whether or not they successfully reproduce future generations that also have this mutation. ...As having an unusual endocrine system apparently worked for the Spotted Hyena.
What are the implications? 1. Secondary sexual characteristics aren’t necessarily set in stone. 2. They are still biologically female, even though they display secondary sexual characteristics of males 3. Secondary sexual characteristics can be the result of natural selection.
Also the bigger and more lion-like physique will take calories to grow and maintain.
So they will use more calories to get the same amount of prey.
It would seem that in an environment with an abundance of prey, but more rivals big lion-like lionesses would be advantageous.
But in an environment with less prey and less rivals, having more efficient hunters would be advantageous.