I have had Wild Dreams since it's release and it always has lots of blooms without pistils, but the blooms that do will set a seed every time. This is the only flaw I have seen in this flower and have not seen this trait in the seedlings. The Tet version has the same pistil problem, Michele gave me two blooms of Tet Wild Dreams and that was the first thing I noticed, no pistil.
All daylilies will have this problem from time to time so it's a pretty common thing.