When exporting a map with a stamp flattened to the foreground, the 2K export shows what is visible in the editor, but the 4K export ignores the mask around the ship. This results in grass, which is not visible due to the mask, being shown in the 4K version, but not the 2K version. What is really annoying about this is to get the 4K to look right, I will have to unmask where the grass is, match the background, and then re-mask the scene.