Contradiction with Joshua 11:21-22
These verses state that Joshua cut off the Anakims from the mountains and left none of them in Israel except in Gaza, Gath, and Ashdod, whereas 1 Chronicles 5:10 refers to the Reubenites defeating the Hagarites in the region of Gilead, not mentioning any Anakims.
Joshua 11:21-22: And at that time came Joshua, and cut off the Anakims from the mountains, from Hebron, from Debir, from Anab, and from all the mountains of Judah, and from all the mountains of Israel: Joshua destroyed them utterly with their cities.
Contradiction with Judges 1:19
This verse states that the LORD was with Judah, and they could not drive out the inhabitants of the valley because they had chariots of iron, which contradicts the success of the Reubenites over the Hagarites with no mention of such difficulties.
Judges 1:19: And the LORD was with Judah; and he drave out [the inhabitants of] the mountain; but could not drive out the inhabitants of the valley, because they had chariots of iron. [drave...: or, possessed the mountain]
Contradiction with 2 Samuel 8:13
David made a name for himself after returning from striking down eighteen thousand Edomites in the Valley of Salt, while 1 Chronicles 5:10 focuses on the Reubenites' victory over the Hagarites, leading to different accounts of military leadership and success.
2 Samuel 8:13: And David gat [him] a name when he returned from smiting of the Syrians in the valley of salt, [being] eighteen thousand [men]. [smiting: Heb. his smiting]