In spite of Engraving Options being set to point all middle-line stems down, my middle-line stems are all pointing up in this file (and some others, for that matter, this is just one example):
FWIW, this file is descended from a MusicXML import. Perhaps that has something to do with it? Nevertheless no amount of resetting/unforcing/whatever will remove whatever is forcing these stems to point up. Anybody know what gives?