They have the IceGuyFX that spawned them as their target instead of the IceGuy that launched the IceGuyFX.
Edit: I apologize, they actually have the IceGuy as their target. However, the reason why I thought they had a wrong target is because anything damaged by an IceGuyFX2 has IceGuyFX as the source of the damage instead of the IceGuy.