The skipping of one generation between Josiah and Jechoniah may simply be following the practice of other genealogies, as in Ezra 1:32 in the Septuagint. It could also just be a translation error.
Between Josiah and Jechoniah only one generation is skipped, namely that of Jehoiakim (see 1 Chronicles 3:15–16). Skipping this specific generation in genealogies had by then already become common practice (see 1 Ezra 1:32 in the Septuagint, LXX, the Greek translation of the Old Testament). Some argue, however, that Matthew 1:11 originally mentioned Jehoiakim and in Matthew 1:12 Jehoiachin (meaning, Jechoniah, 2 Kings 24:6) and that a translator confused the two. This had, after all, already occurred in the Septuagint in which Jechoniah is also called Joakim.1
11 and Josiah the father of Jechoniah and his brothers, at the time of the deportation to Babylon.