Problem with Currie axle, wheel studs?

[Novelli]

The green 67 Chevelle that we built was out with the owner yesterday, when the owner returned back to the shop I noticed that there was a lug nut missing! After further inspection I noticed that it has broke the wheel stud. Three other wheel studs are ready to check out on that same wheel as well. The wheels are billet specialties,(and yes they were torqued) and the axles are Currie. I know the owner drives the car hard, but it def shouldnt be sheering off wheel studs? I am wondering if there was a bad batch of wheel studs out there and I happened to get some. The studs were already in the axles when they came from Currie. Thanks