LCA pivot shaft and adjustable strut rod issues

Some of this is just the norm for scored nuts. The factory used similar nuts on the leaf spring U bolts. Look closely and you'll find a small rectangle stamped into 2 opposing flats. They go on a heck of a lot easier than they'll come off again. Using this type hardware in certain applications is all about safety.
I cant imagine PST having a person checking the quality of every part. Go/no go gauges are time consuming. Regardless... If the nuts they provide destroy the shafts they provide one or the other is out of tolerance. They should make it right.
In the end, Aftermarket is what it is. We have learned ( the hard way ) to reuse our OEM locking ring at the aftermarket fuel senders. I guess we should learn to reuse our original nuts at aftermarket lower arm pivot shafts also. Good luck