Contradiction with 1 Kings 8:9
This verse states that there was nothing in the ark except the two tables of stone, whereas Exodus 40:20 implies Moses placed various items in the ark.
1 Kings 8:9: [There was] nothing in the ark save the two tables of stone, which Moses put there at Horeb, when the LORD made [a covenant] with the children of Israel, when they came out of the land of Egypt. [when the: or, where the]
Contradiction with Hebrews 9:4
This verse states that the ark contained the golden pot that had manna, Aaron's rod that budded, and the tables of the covenant, which contradicts Exodus 40:20 where only the testimony was placed inside.
Hebrews 9:4: Which had the golden censer, and the ark of the covenant overlaid round about with gold, wherein [was] the golden pot that had manna, and Aaron's rod that budded, and the tables of the covenant;