Josephus in [The War of the Jews (Book 3 - 8:9)](https://www.sefaria.org/The_War_of_the_Jews.3.8.9?ven=The_War_of_the_Jews,_translated_by_William_Whiston&lang=bi&with=all&lang2=en) records a story of how he meets Vespasian, tells him that he will become ruler, and Titus will take over his position. Vespasian, although sceptical at first eventually accepts this as a divine message and in the end Josephus enjoys certain privileges due to this. This is apparently referred to as Josephus' prophecy.

This story eerily parallels the gemara in Gittin on the bottom of [56a](https://www.sefaria.org/Gittin.56a.18?lang=bi&with=all&lang2=en) where Rabi Yochanan Ben Zakai sneaks out of the besieged Jerusalem, predicts to Vespasian his promotion and is given his three requests in return.

I am wondering what to make of this. To assume both stories independent and true seems extremely unlikely. Besides the logistics, I doubt Vespasian would feel so impressed and indebted to the second bearer of these tidings. To assume they are both complete fabrications seems extremely unlikely as well. So the two choices left are: someone is misrepresenting what happened, and either way Josephus loses. If he lied and replaced his own self in the place of Rabi Yochanan Ben Zakai, then he has proven himself the liar many have accused him of being. If it was *Chazzal* that chose to rewrite history, we are left to assume that they so despised Josephus that they couldn't relate even one good story concerning him. Is there any parallel to this type of editing by *Chazzal*?
Am I missing something obvious? Any insights appreciated.