o ring issues - are you guys making sure that the o rings are against the top surfaces of both the lower and upper arms? I was having the same issue (rings popping off tightening wheel nuts or leaning on arms) until I realized that I had the upper inserts upside down. the manual has a tiny "flip over" symbol at the upper o ring steps for the upper arm inserts.
Once I corrected the direction, I have not had one o ring come off. HTH