From the article:
> Christie’s marketing campaign was perhaps unprecedented in the art world; it was the first time the auction house went so far as to enlist an outside agency to advertise the work. Christie’s also released a video that included top executives pitching the painting to Hong Kong clients as “the holy grail of our business” and likening it to “the discovery of a new planet.” Christie’s called the work “the Last da Vinci,” the only known painting by the Renaissance master still in a private collection (some 15 others are in museums).
> many art experts argue that Christie’s used marketing window dressing to mask the baggage that comes with the Leonardo, from its compromised condition to its complicated buying history and said that the auction house put the artwork in a contemporary sale to circumvent the scrutiny of old masters experts, many of whom have questioned the painting’s authenticity and condition.
The painting has a volatile sales history, and there's many opinions that it's not an actual Da Vinci. Additionally, it has a lot of flaws that simply make it less valuable, however Christie's marketing has apparently been full-force and managed to fetch this figure. The previous record for an Old Master at auction was allegedly ~$105m taking into account inflation, so this is truly out of left field.