Our 2008 Hawk was built using some kind of sealant where exterior hardware is mounted and where there are joints, including at the edge of the roof. I don't like it much because it oozes out during high temps and it attracts dirt, so it looks blackish. You can see it at the edges of the jack brackets, all the access doors, corner trim, yakima tracks, etc. It's a mess, IMHO.
I had been noticing blackish stains, reminiscent of old bubble gum on the sidewalk, on my liner. I traced it back to the underside of the metal flange where the fabric meets the roof. Using nylon scrapers I went around the camper and removed various gobs of the sealant that had oozed out. I cleaned the fabric (hypalon?) with a citrus based solvent using significant elbow grease. It looks much better now, and doesn't appear to have degraded the liner. I went back later and gave it the 3M 303 treatment.