I don't see that being a fundamental issue of dynamics, but rather of our ability to interpret it. If the Born Rule is an approximation that applies except at the dawn of time, I'm okay with that.

Yeah, that's what I meant by 'revised'. I don't even know if it's possible to find an approximation that behaves sanely. Last time I thought about this, I thought we'd want to avoid the sort of situation you mentioned, but I've been thinking about the anthropic trilemma post and now I'm leaning toward the idea that we shouldn't exclude it a priori.