These cities ... - The text is possibly corrupt. The intention seems to be to state that the cities lying south of the river, though within the limits of Manasseh, were in fact made over to Ephraim, and were among the “separate cities” Joshua 16:9. On the contrary, the north bank of the river, both land and towns, belonged to Manasseh exclusively.
Related Commentaries of Joshua 17:9
Joshua 17:9
9 And the coast descended unto the river Kanah,b southward of the river: these cities of Ephraim are among the cities of Manasseh: the coast of Manasseh also was on the north side of the river, and the outgoings of it were at the sea: