Runes After level up
 

It is supposed to give 12 runes after level up. But when i got lvl 50, it gives me only 6? Why is that, bug or work as intended?

Intended. Your leadership is less too per level.

Reason for this is that dev`s thought in 50 lvls you should develop all skills you wanted, and in game found enough runes for that too.
So after 50th lvl you get 50% runes for secondary skills, just for fun of it.
There is easy way to change this, but i think it will work only for new game, not one already started. If want it ask, i`ll explain.
Also if you want runes, there is always cheat for it.