A new biography of Leonardo da Vinci has raised “a puzzling anomaly” in a rediscovered painting that is estimated to fetch $100m (£75m) at auction next month.

The Salvator Mundi (Saviour of the World) portrays Jesus gesturing in blessing with his right hand while holding a crystal orb in his left hand.

Declared authentic just six years ago, it is to be sold on 15 November by Christie’s New York, which describes it as “one of fewer than 20 known paintings by Leonardo, and the only one in private hands”.

But in a forthcoming study, Leonardo da Vinci: the Biography, Walter Isaacson questions why an artistic genius, scientist, inventor, and engineer showed an “unusual lapse or unwillingness” to link art and science in depicting the orb.

He writes: “In one respect, it is rendered with beautiful scientific precision … But Leonardo failed to paint the distortion that would occur when looking through a solid clear orb at objects that are not touching the orb.

“Solid glass or crystal, whether shaped like an orb or a lens, produces magnified, inverted, and reversed images. Instead, Leonardo painted the orb as if it were a hollow glass bubble that does not refract or distort the light passing through it.”

He argues that if Leonardo had accurately depicted the distortions, the palm touching the orb would have remained the way he painted it, but hovering inside the orb would be a reduced and inverted mirror image of Christ’s robes and arm.

It is all the more puzzling, he notes, as Leonardo was at that time “deep into his optics studies, and how light reflects and refracts was an obsession”.

He filled his notebooks with diagrams of light bouncing around at different angles, he says, wondering whether Leonardo “chose not to paint it that way, either because he thought it would be a distraction … or because he was subtly trying to impart a miraculous quality to Christ and his orb”.

After research, some of the world’s foremost experts confirmed the Leonardo attribution in 2011, when Luke Syson, the then National Gallery curator, included the painting in his blockbuster Leonardo exhibition.

But other leading scholars have doubts. Frank Zöllner, of the University of Leipzig, wrote in an art journal in 2013 that the painting could be a “high-quality product of Leonardo’s workshop” or even a later follower.

Isaacson is particularly interested in research by Michael Daley, the director of ArtWatch UK, who said this week: “There isn’t enough to claim it’s a Leonardo. His figural development was towards greater naturalism and complexity of posture – heads turning this way, shoulders turning the other way, with twists and movement.

“The Salvator Mundi is dead-pan flat, like an icon, with no real depth in the modelling. Another unexplained peculiarity is that the figure itself is heavily and uncharacteristically cropped.”

Daley also pointed out that optical deflections appear in an engraving by Wenceslaus Hollar, the 17th-century etcher, from Leonardo’s original composition, dismissing the suggestion that “Leonardo knew all about the optics, but just decided not to bother”.

Christie’s dispute this, saying the engraving referred to does match the painting.

Isaacson said: “When you balance the evidence for and against...then that is a valid point, that Hollar would not have distorted the robes if they hadn’t been in the original painting. In other words, I’m saying that Michael Daley, I think there’s always arguments for and against. You have to do a balance. If you look at the Hollar engraving, and if it is much different, that counts against it being the original. But I’d defer to Michael to say that. I try to present arguments on all sides. I don’t pretend to be as good as Michael Daley.”

In studying optics, he spoke to numerous science experts. Asked whether he would invest in the painting if he had $100m, Isaacson said: “The preponderance of the experts is that it is authentic, and so I would - but that doesn’t mean that I’d be absolutely sure. I’m a little bit more leaning towards the fact it’s authentic than…Michael Daley seems to be.”

A Christie’s spokeswoman said: “Leonardo’s paintings are known for their mystery and ambiguity. He was intimately familiar with the technicality and qualities of optics and light. If he had recreated the image with optical exactitude, the background would have been distorted.

“It is our opinion that he chose not to portray it in this way because it would be too distracting to the subject of the painting.”

Paramount Pictures has bought the rights to Isaacson’s book and Leonardo DiCaprio plans to make a biopic inspired by it.

• 24 October 2017: this article was updated to extend the context of the quotes from Walter Isaacson and to include Christie’s statement that the engraving referred to by Michael Daley does match the composition of the painting.