Update on this, I finally had a chance to take a look at the code. It actually turned out to be a much bigger bug than expected.
The Truesight spell was setup correctly.
The actual problem was buried in our magic system where spell difficulty for offensive spells is actually computed. One of the modifiers it computes is KS based, so a caster has an easier chance at same sized or smaller kingdoms, and a more difficult chance for larger kingdoms. Unfortunately a < should have been a >. It has been working the opposite of how it was intended all this time... Meaning before it was easier to cast on larger kingdoms, and harder to cast on smaller/same sized.
It's fixed now, it will be a lot harder for small casters to successfully cast offensive spells on larger kingdoms now, as it should have always been 🙂
