> Utter nonsense. John DeFrancis debunked your interpretation of this drawing back in 1989. This is not a letter at all. It was a prop in a parlor game played by Yukaghari girls: one girl would sketch a drawing and the others would take turns trying to guess the story behind it.
> Geoffrey Sampson helped to propagate this myth in his book on writing systems first published in 1985. Sampson published a retraction in 1994.
While I could not find any verification in a cursory search, maybe we should take this with a grian of salt