Beats me, but I don't see how a system that's not guaranteed to keep its values fixed in the first place can be relied upon not to store its values in such a way that epistemic insights won't alter them. If there's some reason I should rely on it not to do so, I'd love an explanation (or pointer to an explanation) of that reason.

Certainly, I have no confidence that I'm architected so that epistemic insights can't alter whatever it is in my brain that we're talking about when we talk about my "terminal values."