I bought the Corratec that Matt-b had for sale here as I wanted quite a few of the bits for one of my builds. Matt was completely honest about what his LBS said about a possible crack/paint scratch but I wasn't too concerned as I wasn't buying it for the frame anyway.
My plan is to sell the frame but whether I advertise here or somewhere else I want to be completely honest about the discussions on here regarding the frame. The marks were barely noticeable to be honest but I decided to clean the paint off for a better look. I appreciate that looking at photos doesn't compare to the real thing but was looking for other people's opinions.
I'm no expert but it looks fine to me!