When you remove all of the studs it would be interesting to use a torque wrench and see how the torque compares to the original installation torque (especially on the remaining rear wheel). I wouldn't be surprised if you found more cracked studs either.

 

Might be difficult to get a break away torque if Loctite was used.

 

I had two right rear studs break off at WGI two years ago. I wouldn't have known about it until too late, except some one found one of them on pit out. They were new within the past few months, and were good that AM when I again checked my wheels. Since then, I replace them every second year.