Your champions may not have had tarhh blood

It is supposed to be a race trait

Dont pay ofr certain terrain types and monsters inclined too leave your tarth units allone

It was wildlings that attacked me so that does seem to be it and this isn't a bug. The problem I have with that is that this isn't anywhere in the trait description. Nothing frustrates gamers more than seemingly arbitrary game behavior and a lack of information about what's really going on. If Wildlings are exempt, I hope they will add a short sentence to the trait description saying so.

You right that master scouts trait needs to be updated to say the mundane monsters won't attack your units. There is an exemption with the Wild-land denizens. So, I would say that we should update the description of Master Scouts to say

Mundane monster won't attack units. No movement penalties in Forests, Swamps, Hills or Rivers.

Or what ever word works best for Mundane to represent that your normal monsters won't attack, but special monsters like the Wild-land denizens are able to attack your units. Good post.