This is the third control arm I have seen with this problem. The OE brackets are only 1/8" material and there is insufficient material surroundling the bolt hole. To the OP, where the nuts loose on the end link when you found it this way?
During our control arm testing, we actually updated the sway bar mounts on the control arms specifically because of these failures. The sway bar mounts were increased in thickness to 3/16" material and the hole has a full 1/2" of material around it's radius...