Very common to find the rear hood rusted out behind the decals on the 20 series. Seems to be worse on the Titian II's, maybe thinner metal. I've seen Titian II's that have been shedded since new with bubbles behind the decals. They just get washed and maybe caught out in a few rain storms over the years and the crap gets wet and rusts the tin. Its so common that the top rear hood and lower inner and outer side panels are available new aftermarket for the 20 series combines. The new hoods are of a open design, no place to trap trash. Deere's engineers were sure not thinking ahead when they designed the rear hoods on these machines.