On the Hard and Expert difficulty settings (and I'm assuming higher settings as well) AI units get extra traits. On Hard each unit gets Strength (+2) and on Expert each unit gets Bloodthirsty, Strength (+2), and Ironskin. 

Is this a bug or is it by design? I can't tell.

The reason for thinking this is not by design is because Strength and Bloodthirsty are both from the hero level tree (ie StrengthAbility_Level) and are not the traits with which units are designed. Also, in a recent game, the AI stopped producing units with these abilities suggesting those added traits are not in fact connected with difficulty levels.

If this is by design, that's OK (though I think Bloodthirsty should be changed to Fast or Constitution). Either way something isn't working quite right.

Thoughts?