Necromancer Summon Oddity(Liches)

[PurpleXVI]

Several times now, when I've been lucky enough to have multiple liches marching around with me, they appear to have gotten into fights with each other. Not just friendly fire accidents.

As far as I can tell they can aggro each others' summoned Shadows which then just start mercilessly trying to kill the Lich that pissed them off, who won't fight back(though, I think HIS Shadows might get in on the fighting themselves).