Not strengthening the Dutch family.
I don't know how many times I have strengthened Dutch family 2. I never seem to graduate past 4/5, even with all correct answers, at increasingly lightning speed. I am tired of being Cinderella -- it was funny the first time. What gives? Many thanks.
This is a bug that several people have encountered, unfortunately; it happens to me about once a month. Try redoing the actual lessons in family 2, starting with the last one and working your way backward until it turns gold again. Usually the last lesson is enough on its own for me, but occasionally I have to do one or two more.