Steve Mason, “Was Josephus a Source for Luke-Acts?” in On Using Sources in Graeco-Roman, Jewish, and Early Christian Literature, edited by Joseph Verheyden, John S. Kloppenborg, Geert Roskam, and Stefan Schorn (Peeters, 2022), 231.
To sum up this section: the several puzzles of Acts 21,38 – (1) that Luke would choose Latin sicarii for Judaean militants, (2) that he should locate them out in the desert rather than in the city, and (3) that he should place the Egyptian at their head – are not well solved by imagining another source that made such a combination. They are most economically explained as the author’s blending of elements from a dense passage in Josephus, War 2. Looking for another source would leave us with more problems: What other author had the compositional interest in (a) highlighting the desert as the destination of false prophets, (b) positing sicarii in Judaea in the first place, (c) portraying them as a group, and (d) isolating an unnamed Egyptian, all in close proximity? Differences here speak for Josephus’ influence.
The Amateur Exegete 