Contradiction with Leviticus 7:34
Leviticus 7:34 assigns the breast and shoulder of the wave offering to Aaron and his sons, contrasting with Numbers 6:20 where they are waved and then returned to the person.
Leviticus 7:34: For the wave breast and the heave shoulder have I taken of the children of Israel from off the sacrifices of their peace offerings, and have given them unto Aaron the priest and unto his sons by a statute for ever from among the children of Israel.
Contradiction with 1 Samuel 2:28
1 Samuel 2:28 states that the priesthood and its offerings would be sustained by offerings from the people, suggesting a different allocation than the Nazirite offering in Numbers 6:20.
1 Samuel 2:28: And did I choose him out of all the tribes of Israel [to be] my priest, to offer upon mine altar, to burn incense, to wear an ephod before me? and did I give unto the house of thy father all the offerings made by fire of the children of Israel?