I dont know why a welded front would cause knuckle studs to shear.
The front end wants to go straight and you are putting a lot of pressure on them by forceing it to turn. It is worse if they are not torqued to spec. You will also find that most of the time the studs on the PS side are the ones breaking with hy-steer. The two times I broke them they were on the PS making a hard right turn.
