Contradiction with Deuteronomy 3:11
Og king of Bashan is described as the last of the Rephaim, suggesting a time before his defeat, while Joshua 12:5 claims the land was taken over by the Israelites, contradicting the notion of him being the last.
Deuteronomy 3:11: For only Og king of Bashan remained of the remnant of giants; behold, his bedstead [was] a bedstead of iron; [is] it not in Rabbath of the children of Ammon? nine cubits [was] the length thereof, and four cubits the breadth of it, after the cubit of a man.
Contradiction with Judges 1:27
The failure of certain tribes to fully conquer their allotted territories contradicts the assertion in Joshua 12:5 of complete Israelite control over specific regions.
Judges 1:27: Neither did Manasseh drive out [the inhabitants of] Bethshean and her towns, nor Taanach and her towns, nor the inhabitants of Dor and her towns, nor the inhabitants of Ibleam and her towns, nor the inhabitants of Megiddo and her towns: but the Canaanites would dwell in that land.