When I did my front control arms, I marked the original position carefully. Removed the old arms, installed the new OEM arms, carefully put the hardware back to my original marks, and torqued CAREFULLY to FSM spec. Took it for an alignment. Then, put it back on my lift, and retorqued just in case the shop loosened something. I never had an issue with anything slipping after that.
I don't know if it's a "bad" design... but there are sure "better", lol