This artwork is discounted because of a very minor red signature ghost. The red ghost is very faint and blends in well (you won't notice it unless you very closely inspect the painting).

If you are wondering, red ghost refers to a red shadow of the artist's red signature stamp. This is sometimes transfer from a previous painting which happens when the artist signs all of his work at the same time and piles up the paintings before the red ink is dry. It's more common than I would like, and it costs me a lot of money - but I am picky about quality, so my loss is your gain.