Contradiction with Numbers 1:1
Numbers 1:1 states that God spoke to Moses in the wilderness of Sinai on the first day of the second month, in the second year after they had come out of Egypt, while Numbers 3:14 suggests the setting is slightly different without specifying the time as clearly.
Numbers 1:1: And the LORD spake unto Moses in the wilderness of Sinai, in the tabernacle of the congregation, on the first [day] of the second month, in the second year after they were come out of the land of Egypt, saying,