Reasons why the computer will not cast the spells you script

[tinkthank]

I have often noticed that some of my favorite scripts (power of the spheres, phoenix power, flame arrows, wind guide) do not get cast but rather astral shield followed by something I dont want DESPITE the fact that the commander definately has enough gems on him. So what reasons could there be in those cases?

Since my searches on this topic turned up either inconsistancies, I thought I would start a thread here and hope people would add.

To my knowledge, the tactical AI spellcasting will not cast your scripted spells if they are
- impossible to cast (e.g. underwated/land conflict)
- you dont have enough gems
- if you scripted Quickness, your following spells might get replaced by some random spell you get from extra "quickness" spell (I think??)
- there is no appropriate target (in range)?? (is this right)?
- when else?