The mouse over shows no info about group bonus caps, unlike max strength caps.
A HorseLord with +25 Leadership and a red Dragon with +10 Moral yield +30 Bonus (if the enemy has no specials). However, the battle info does not show that the bonus is capped. There is no "max" or blue triangle displayed, unlike for other caps.
This proved confusing for a new player that we are introducing to the game.