John Gill Commentary Joshua 17:8

"The land of Tappuah belonged to Manasseh; but Tappuah on the border of Manasseh belonged to the children of Ephraim." — Joshua 17:8 (ASV)

[Now] Manasseh had the land of Tappuah
The whole territory that went by that name, from a city of note in it, next mentioned; all the fields and villages in it belonged to the tribe of Manasseh:

but Tappuah on the border of Manasseh [belonged] to the children of
Ephraim ;
and was one of those separate cities they had among the inheritance of the children of Manasseh; though it seems they had only the city, not the territory adjacent to it, and which was named from it.