You are not missing anything. It is a combination of your mapping: a) child does not have a Parent mapped, b) child is versioned, c) collection is not set as inverse (because it cannot be managed by child without mapped parent) d) and finally, most likely due to a bug.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.