So usually I see the CPU using the skill of Retrovirus when it has something to gain from it (Boneyard, Bone Wall, me having creatures out), but just now Incarnate used it despite nothing to gain. I assume it has to do with the 0 cost, but it's pretty crippling for 'em. I also see their behaviour has gotten more random, but I think there should be a logic that stops them from doing it unless they have at least something to gain.