I am writing up a island covenant in a Regio which has Inhuman Covenfolk. (Marshwiggles, but that has little to do with the question being raised) As they are grogs, they only have a Might score of 3. I was thinking that they would fish outside the covenant grounds, which would put them outside the aura for long enough periods that they would suffer acclimation. It is simple enough for the magi to invent moon duration spells that would be constantly in effect over a marshwiggle, but it does raise the question of warping. I seem to recall that magical creatures do not receive warping from magical effects, but I can't find it in my books. Am I making this up?
Nope, thats RAW. Magical creatures do not suffer warping as they are inherently linked to the magic realm. "Creatures with Might scores are absolutely immune to warping". See box text on p.167 of core rules.