Back in college around 1975, I wanted to see just what Josephus had written, so I looked up a compilation of the Greek manuscripts. I went to that page and right there in the original Greek I found ... nothing. That text was not there.
No, wait, there's a footnote! In the footnote, the author noted that that text does not appear anywhere in the original Greek. And that the earliest that it does appear is much later in an Old Church Slavonic translation.