Suppose that a founder (or other prominent adherent) of some philosophy theory X later comes to repudiate this theory. Does their conversion have epistemic significance for onlookers to the debate over X?
It's often treated as evidence against X. ("Even prominent X-theorist Jane now realizes that X is fundamentally flawed!") This may be understood against the background assumptions that people typically suffer from confirmation bias, and that motivated reasoning will be especially strong in case of a view that's become entrenched in one's sense of identity. Surely, we may think, it would take compelling reasons to overcome such strong biases and cause a prominent adherent to repudiate their theory. (Okay, that's not the only possible explanation, but it might be one of several that receives a significant credence boost, thus justifying a lower credence in X.)
On the other hand, the fact that Jane changed her mind is evidence that she is less biased and irrational than your average Joe. So maybe her views -- including her past views -- are worth taking pretty seriously. This might not lead you to think X more likely true, but you might at least look more carefully for other virtues of the theory that you'd previously overlooked. After all, if someone like Jane once believed it, it can't be completely idiotic. (Well, it could be, but we're talking about shifts in your balance of credence here.) So if you previously did think X completely idiotic, I guess it's conceivable that this might actually boost your credence in X ever so slightly!
I just found that curious. Either way, I don't expect it matters much in practice, as this kind of meta-evidence will typically be swamped by the first-order reasons for or against X.