So... this whole idea of the tapered and threaded sleeve for the pinch bolt is not safe out of the box imho, you just screw a sleeve that is tapered in the upper half onto the ball joint. No set screw, no way to hold the ball joint to stop it from spinning while you try and tighten it on, and no instructions to tell someone to put locktight anywhere. I can see why someone who isn't mechanically inclined might throw this together and it come apart a few rides later.
So here is what I did to remedy this problem. First, I put a generous helping of red locktight on the ball joint threads and screwed the sleeve on by hand, then got some channel locks and gripped it then smacked them with a hammer to tighten it a little more (might have gotten it a little tighter but ball joint spins pretty easy). After that I installed the spindles. Then I got 2 m10x1.25 bolts and threaded them in from the bottom with a little locktight and tightened them to act like a jam nut, but its a bolt. Jam bolt? Idk, but I feel much safer with it in there. The shortest bolt lowes had was 25mm, it needs to be about 8mm, I'll cut it down later.