got a response back from Tein. They're saying I need to preload my suspension while I do the install. it "seems" to make sense, I never thought you need to preload suspension during an install
"Please read our blog on applying suspension preload.
http://teinusa-blog.com/applying-suspension-preload/. This should clear things up what we mean. This is what seems to be the issue. Your OEM arms had tension from the vehicle being at a higher height and when you lowered it. You did not loosen the lower control are bolts, and add suspension preload. So when you were driving on a twisty road that was enough force to break the tension, and in turn lowered the vehicle. You will be re torquing all locking collars and the top nut to our factory specs in the manual. Please make sure you use the manual to find the torque specs. All specs can be found in the manual on the assembly diagram page."