Doomed shadow AI is badly buggy.

[PurpleXVI]

I've so often seen shadows attack apparently friendlies, including each other, and escorts. When playing as a Necromancer, on the occasions you get more than one lich, two different liches' shadows may attack each other, too, despite ostensibly being allied. This never happens with any other summons or allies in the game, it's just shadows, which is weird since they so often seem to faff around in circles instead of attacking actual enemies.