Contradiction with Joshua 13:14
Joshua 21:1 describes the giving of cities to the Levites, whereas Joshua 13:14 states that the Levites received no inheritance among the Israelites, only the offerings made by fire to the LORD.
Joshua 13:14: Only unto the tribe of Levi he gave none inheritance; the sacrifices of the LORD God of Israel made by fire [are] their inheritance, as he said unto them.
Contradiction with Joshua 21:43-45
Joshua 21:1 implies a distribution not fully realized yet, while later verses affirm that the LORD had given all the land and rest to Israel, fulfilling His promises completely.
Joshua 21:43-45: And the LORD gave unto Israel all the land which he sware to give unto their fathers; and they possessed it, and dwelt therein.
Contradiction with Deuteronomy 18:1-2
Joshua 21:1 discusses the allocation of cities to Levites, while Deuteronomy 18:1-2 states Levites have no inheritance, only the LORD as their inheritance.
Deuteronomy 18:1-2: The priests the Levites, [and] all the tribe of Levi, shall have no part nor inheritance with Israel: they shall eat the offerings of the LORD made by fire, and his inheritance.
Contradiction with Numbers 18:20-24
Joshua 21:1 arranges for Levite cities, contrasting with Numbers 18:20-24 which claims Levites have no share in the land, only tithes as inheritance.
Numbers 18:20-24: And the LORD spake unto Aaron, Thou shalt have no inheritance in their land, neither shalt thou have any part among them: I [am] thy part and thine inheritance among the children of Israel.