Ghosts and "Out of Control" - how it works?

[BB Shockwave]

In my previous Game as a Paladin, I often used Sacrifice to replenish troops I had no source of getting again (Evil Beholder, Shaman). There were cases when this caused them to go over the leadership limit with 2 or 3 units, in this case they just became out of control (a yellow crown icon appears) and ran around the map, not attacking anyone, not even the enemy. If the last enemy died, the battle was over and I just had to dismiss these extra units.

Now I'm playing with a Mage, using an undead-only army (with Werewolves too) - the ghosts are a major annoyance. Even if they go over the leadership by one ghost, they go out of control with a RED mark and broken crown effect, and start attacking my troops or the enemy at random. Worse yet, the battle is not over until you kill the excess units - hard to do without killing too much of them...

So, is this only for ghosts? They have a different 'over leadership' script then other units?