I purchased a new Salem BKIS back in February, a few months back I noticed several black lines going across the roof. Also the black lines extend the entire length of the trailer on both sides. These lines appear to be a form of mold or something similar. When I got on the roof I found that every line was where the plywood roof panels met. As well the outer edges is where the plywood ends just above the gutter. The molded areas are not sunk in or in low points. I had a Salem before this trailer and never had this issue. Just wondering if someone has seen anything similar or any ideas on what it might be. I have attached pictures, I think! Thank you!!!