Watch pariden fighting air shrills, they take every opportunity to waste mana on soul sparks when the battle could already be over with a few physical attacks. Sucks, makes autoresolve unusable for certain mobs.

Natures Blessing FTW

Many A time I have had 6-8 earth shards, buffed my entire army and attacked shrill lords, dragons or elemental lords. Its always great when they waste turns casting spells at me.

So the AI needs to not only recognize 100% immunity but recognize 90% immunity.