Your caching is definitely not coming from Apple's code because they know that the cache is in Core Data.
Based on the code posted and the problem description, I suspect that the categoryEntityDescription property is returning nil.
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.