Mistakes in illithid behavior

In mod 17 expeditions, Ilithilichs walk around with the living mind flayers, intellect devourers and cooperate with them fight against player but dont't combat with each other. In d&d lore living ilithilids hates undead kind of it's race and hunt for alhoons and illithilichs. Lich are enemy of the living mind flayers because reject of his society circle of life, culminating with the merging with an elder brain. I think solution for mod 17 is replace model of Ilithilich to Ulitharid or add more ceremorphosis/related creatures.