Contradiction with 1 Chronicles 18:11
This verse lists similar spoils but mentions additional groups like the Edomites, which suggests a different account of who David took spoils from.
1 Chronicles 18:11: Them also king David dedicated unto the LORD, with the silver and the gold that he brought from all [these] nations; from Edom, and from Moab, and from the children of Ammon, and from the Philistines, and from Amalek.
Contradiction with 1 Samuel 15:3
In contrast, this verse commands Saul to utterly destroy the Amalekites and not take spoils, conflicting with the practice of taking spoils in 2 Samuel 8:12.
1 Samuel 15:3: Now go and smite Amalek, and utterly destroy all that they have, and spare them not; but slay both man and woman, infant and suckling, ox and sheep, camel and ass.