Stains on leatherette upholstery in very good condition. Could be due to chemical products, maybe not rinsed?
They look like rust stains. Some idiot could be grinding steel/iron nearby. Could even have sat on it. A gentle scrub with an old toothbrush with either lemon juice or white vinegar should lift it. The other half of the Lemon? G+T please, jolly cold.
People from the shipyard say the stains are due to wear and, if cleaned, will come back. My opinion could be different, but I am not an upholsterer or a "Bloodstain Pattern analyst". I cleaned one, and the leather is not cracked but without stains.
We had many customers come up with simular stains in their seat covers. I never got the hard story but the conseses was a fungus and non correctable. Have you discussed this with the Mfg or material supplier ?