Why does it say that there were 22 cities? The verses list 23!
Malbim (29): Ir Mivtzar Tzur was in Naftoli (verse 35
Refer to 19:6:2:2 and the note there.
There it says Tzer with a Tzeirei, and it is listed with other Arei Mivtzar after the verses detailed the borders. (PF)