Is this a wheel stud safety issue?

2005 ford focus zx5 hatchback

Got it cheap, noticed the rear driver wheel had a new stud but looked like the lug nut wasn’t seated as far as the other 3 on the wheel. Took the wheel off and found this. The new stud looks to be 4mm shorter and can also see that is looks like nothing has been seated properly on that stud even before they replaced it. Should I open it up and try to pull it through more or replace entirely? Thanks