I have a similar problem with villagers becoiming masters in anything but research. I started four villagers off at the same time to develop their skills, two in research and one each in farming and building. The two in research plus two more have already become Master Scientists while the builders and farmers (who I might add have worked as diligently and continually as did the others) have not progressed from Adept status. What's the deal?

P.S. You may e-mail me with advice. I don't always get into this site since I am always fighting my grandson for computer time. That's what I get for showing him my VV: TLC