Contradiction with 1 Samuel 31:6
While 2 Samuel 4:1 discusses the fear of Ish-bosheth after Saul's death, 1 Samuel 31:6 confirms that Saul and his sons were already dead, suggesting a time contradiction or confusion in the reaction timing.
1 Samuel 31:6: So Saul died, and his three sons, and his armourbearer, and all his men, that same day together.
Contradiction with 2 Samuel 2:8-9
These verses state explicitly that Ish-bosheth was made king by Abner immediately after Saul's death, but 2 Samuel 4:1 suggests a change in his strength and resolve, contradicting his earlier position of power.
2 Samuel 2:8-9: But Abner the son of Ner, captain of Saul's host, took Ishbosheth the son of Saul, and brought him over to Mahanaim; [Saul's host: Heb. the host which was Saul's] [Ishbosheth: or, Eshbaal]