if you start off adding dynamic (mf, p, ff) beneath the note (normal), then the next dynamic added will have intended effect. If you at some point add a dynamic above a note, the dynamic will change... but all subsequent dynamics must be above to have an effect. (Note that dragging an existing mark up/dn doesn't change this).
If I discover this, I select a single part view, and work backward in score until I find the wayward mark, then delete and add below.
