[ The longer they talk and the subject is of interest to him intellectually, the easier Waver's body language becomes; he relaxes, the discomfort and awkwardness fading in the face of this new problem taking his concentration in a less personally fraught direction. ]

You're right. I heard something similar, though I'm not sure how far the problem's spread. If the moss has such a strong effect against the Cwyld, it's definitely bad news if something's destroying it, even if it is a natural occurrence.