Disappearing Affliction?

[Thufir]

I've just recently had a pretender fighting off a bunch of indy barbarians, and during the course of that fight got a "weakness affliction". To my surprise, the affliction disappeared after combat. I was not running GoH, nor did I have the Chalice, nor was their any character capable of healing in the province.

During that fight he was running regeneration, which I understood to reduce the risk of getting an affliction, but not to heal an existing afflictions. Or is that the way regeneration is supposed to operate in terms of affliction risk reduction - any affliction you would've gotten during combat shows up, but if the regenerative affect kicks in, it then disappears at the end of combat?