This is a bit of an on going item that was started by Jon.
LINK. He posted the file with the same background burgundy colour but it also had horizontal bars with linear fills from white to the same burgundy as the background colour. At first it looked like the linear fills were incorrect in the final pdf. After a bit of head scratching it was discovered the burgundy in the linear fill was correct but the background wasn't. Why was the linear fill's burgundy correct in the pdf but not the background rectangle?