Contradiction with Exodus 23:16
This verse states the Feast of Ingathering is at the end of the year, while Numbers 29:12 specifies the seventh month.
Exodus 23:16: And the feast of harvest, the firstfruits of thy labours, which thou hast sown in the field: and the feast of ingathering, [which is] in the end of the year, when thou hast gathered in thy labours out of the field.
Contradiction with Deuteronomy 16:13
This verse mentions the Feast of Tabernacles lasting seven days after gathering in thy corn and wine, but Numbers 29:12 specifies starting the fifteenth day of the seventh month.
Deuteronomy 16:13: Thou shalt observe the feast of tabernacles seven days, after that thou hast gathered in thy corn and thy wine: [corn...: Heb. floor, and thy winepress]
Contradiction with Leviticus 23:34
Contradicts the start and details of the feast, focusing on a different aspect of celebration.
Leviticus 23:34: Speak unto the children of Israel, saying, The fifteenth day of this seventh month [shall be] the feast of tabernacles [for] seven days unto the LORD.
Contradiction with 2 Chronicles 8:13
Describes a different schedule and offerings from Numbers 29:12, adding confusion to the timing and nature of the feast.
2 Chronicles 8:13: Even after a certain rate every day, offering according to the commandment of Moses, on the sabbaths, and on the new moons, and on the solemn feasts, three times in the year, [even] in the feast of unleavened bread, and in the feast of weeks, and in the feast of tabernacles.
Contradiction with Nehemiah 8:14-18
While referring to the same feast, emphasizes dwelling in booths which is not mentioned in Numbers 29:12.
Nehemiah 8:14-18: And they found written in the law which the LORD had commanded by Moses, that the children of Israel should dwell in booths in the feast of the seventh month: [by: Heb. by the hand of]