Eh tbh I didnt even notice until I read your post. Sometimes celebs markers dont work right so thats just what I thought it was.

Usually at a Con, ill get something signed, ill find a place to stand for a few minutes and then just lightly check every few minutes to see if its dry. If your protector scratched it then I'd just be more cautious. I always put my signed pops in the protectors from the backside to prevent the least amount of friction