The seat covering is attached to the seat-pan with staples, and on mine two of the staples stuck out from the seat-pan and dug into the paint of the tank. I hammered them in, and am planning on coating the front of the seat where all the staples are with "Goop".
You would think they would know about this kind of stuff after building bikes for so long...
Oh well. Small problem, and love the bike anyway.