This can easily be fixed! That mark can happen if you hold the section too taut when inserting in the clamp or when you rotate the barrel so that your hair folds backwards over the clamp. If you start to get kinks in your curls from the clamp, try rotating the barrel in the other direction.
You can watch this video on our TikTok that will help you get rid of clamp kinks: https://www.tiktok.com/@thebeachwaver/video/6984909892075146501?is_copy_url=1&is_from_webapp=v1&q=Beachwaver%20clamp%20kink&t=1638549704523