Well, it was very embarrassing to take a victory lap with the war getting bogged down, and revealed motivations for the war that contradicted Putin’s statements, and aligned with the “blitzkrieg” analysis of Russia’s early failures.
So, true, it’s not proof, but Occam’s Razor comes into play here.
Was this published on accident? Or was it intentional? There is no way to know for certain.
Think about this piece of evidence as a data point, but one that is nowhere near damning proof.