I just noticed that the tension jaw makes these tiny vertical marks on my strings(not gut). I can feel it scrapping against my finger. They are not deep cuts. So far they are not a problem on my Poly, Multi or Synthetic strings both 16g & 17g. I don't think that will be good for natural guts. I adjusted the gripper so it's not too tighter but not slipper but the marks are still there. Is there anything I can do?