I have this quote in my mind,but I cannot find the source for it: "Someone who claims to predict the future is lying, even if later proven right". I thought it was a variation of something in the Quran, but neither ChatGPT nor Google can find it.
It seems that this is just a paraphrasing of an Arabic proverb, with no specific source. See https://allauthor.com/quotes/107770/
It is often given online as "he who foretells the future lies, even if he tells the truth"