There appears to be conflating traditions concerning where Aaron’s budding rod was relegated.
But when the author of Hebrews six centuries later duplicates this tradition while speaking of the first Temple, he places Aaron’s budding rod in the Ark!
He also—and I missed this in our Exodus contradictions—places the the omer of manna collected in the manna story in the Ark too, rather than in front of the Ark as stated in Exodus 16:34.
Lastly, the Hebrews’ account then states that the Tablets of the Covenant were also in the Ark. This too conflates with the Priestly traditions since in P what are placed in the Ark of Testimony are the Tablets with the instructions of building the Tabernacle! See #156.
Finally, both 1 Kings 8:9 and 2 Chr 5:10, which reproduces the account in Kings, contradict the account in Hebrews. For both these texts state that: “There was nothing in the Ark save the two Tables of stone which Moses put there at Horeb.” This matches both the Elohist tradition now in Exodus and the Deuteronomic tradition.
Why then did the author of Hebrews change this? Minor oversight on his part? Or did he change this on purpose to express a personal agenda of some sort? My initial response is to say neither: most likely he was reproducing a 1st century CE oral tradition that had veered somewhere in its transmission from the written text. — just a guess.