Oh wow, you are correct about the Terrain skill, I completely missed that.
And about the "Fatigued" debuff, I mean it lasted forever, all the way until turn 35. Whether it truly impacted my skill checks, I don't know, but my skill screen clearly showed those "double bars", with the top one being my normal skill and the bottom one missing 10 points in red.
Thanks for the reply, I love your game and I plan to discover *everything*.