Hmmm not sure about that one. My issue was different because my dogbone wasn't sitting half as far back in to the cup when sitting still as yours are. IDK how that dogbone could get enough play in it to pop out. Its sitting where it should in the diff cup.
Do both kits have HR steering knuckles?
I had this happen with a rear dogbone on my K8, I can't remember what I had to tighten up to make it fit in the diff cup better. I wanna say it was the rear turnbuckles but I can't for the life of me remember.
Need more pics. can't see the dog bone or the diff cup in that pic.