KO, would it help if you had a bundled, sorted collection of the turn files, map files, and the fatherland files for the individual battles in question where the spell casting goes awry?
I know I've kept most of my turns for sloth, and I can provide you with multiple instances of arrow fend being cast for no reason. Also, there was a huge battle where R'yleh had undead mastery ready to cast in a big communion with over 5k+ undead in the battle, but instead cast bone grinding
Maybe it would be helpful if you could modify the values for the decision making process, and then "rehost" the turn to run it through a real life example to see how it would change the outcome.
Jazzepi