PINCHED NUTS QUESTION

The OEM nuts on axle U bolts have tiny square impressions in 2 opposing sides. They were stamped, clamped, pinched, distorted. I've heard these called scored nuts too. Anyway, thats is where my thought went when I read "pinched".
The term for the nuts you are questioning in the beginning of the post is I believe called Schrader nuts and are considered zero tolerance and essentially act as lock nuts. I made a mistake a long time ago thinking I stripped a thread but that is how they are supposed to feel when installing them.