He does have the luck category, which Auburn is ranked #1 in the country. The luck ranking measures the deviation between a team's actual winning percentage and what one would expect from its efficiency numbers. Simply put, a team that's in a lot of close games, will win close to 50% of those contests. Auburn is 12-0 in single-digit games, including 5 overtimes and one regulation buzzer-beater. That is not normal.
On top of that, 9 of those 12 close wins are against teams ranked outside of the top 50. So you're talking about a lot of close wins against sub-par competition. When you factor in two blowout losses, it's really not that surprising that Auburn's ranking is so low, in spite of a very impressive record.