NotePerformer 3.1 Xylophone Playback

I just discovered that NotePerformer 3.1 plays back the xylophone at written pitch instead of an octave above written pitch as it ought to be. I switched the xylophone to HALion Sonic SE in Play Mode, and the Halion xylophone correctly plays back an octave above written pitch. So this appears to be a NotePerformer issue. Has anyone else run into this?