Family members culled from new family tree

The new family tree since the Royalty & Legacy ex pack looked and seemed to work very well to start with. Now I detected that several family members only two generations back are greyed out. They are grandfathers and grandmothers of the living sim. Who forgets their own grannies? But worst of all is that a great grandfather is remembered but not his children , thus the grannies of the now living sim. So the child forgot his grannies but remembers his great grandfather. Please don't cull close family members to living sims from the family tree. It destroys this very good family tree update.