I'm not sure if this is a bug or not, but in my current game I've noticed that I'm not getting any naval commanders above the rank of Captain (using the US rank system).
I'm running v2.1, realistic promotions is turned and political bonuses is turned off. The game has been going on for 54 years, I have one level 5 academy on Earth with a naval commander assigned and the race-wide training quality is set to 5. My current naval commanders are as follows: 357 lieutenant commanders, 47 commanders, 7 captains, and only 3 admirals (2 lower and 1 upper) which I had to manually promote to command my two diplomatic ships and the academy on Earth. I'm using automated assignments and have the fleet admin commands setup to be automatically assigned as well, but all of my fleet admin commands are currently empty because all of the people that I manually promoted to command them have retired and the game hasn't promoted anyone to replace them.
The ground force commanders are better distributed, though I have no majors at the moment, but I'm pretty sure that's because the majority of my formations require a lieutenant colonel or above.
This is the only game that I've played on v2.x. Has anyone else experienced this issue with the naval commanders?