Alan,
Do you expect that the Single Stone Competition page will get updated with the 2018 competition designs anytime soon?
While I cannot disagree with Dennis’ assessment/puzzlement with using Feldspar for the Kiev, I can only say that the rules state that materials will get changed up from year to year, and feldspar is one of the recommended materials for the Grand Master Class. Difficulty would be my guess as to why it was selected. It finished a pretty gem, and does not window as poorly as suggested, but not the prettiest I have seem by any means.