Contradiction with Numbers 21:35
This verse describes the Israelites defeating Sihon and Og, leaving no survivors, which contradicts the claim in Joshua 13:12 that areas remained that were not conquered, including the lands of Og in Bashan.
Numbers 21:35: So they smote him, and his sons, and all his people, until there was none left him alive: and they possessed his land.
Contradiction with Deuteronomy 3:11
This verse states that Og, king of Bashan, was the only remnant of the giants left, implying there were no more giants, which contrasts with Joshua 13:12, where the remnants of giants are said to remain in Bashan.
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.