Dear Sir,
The clue of the rust that could be from the water get into the compressor, You also known that the compressors or dryers left the factory with fully tested and clean without any rust, and the VCI paper also put into the cabinet to avoid the moisture in the cubicle.
Kindly please investigate with the root of this machine, which you can check starting from manufacturing date, which port of shipment, when the machine arrived, when and where machine stock.
The logistic will give you more information on this matter,