Using EDxx, when playing a note on the same tick as the following note, even though note 2 is also using EDxx, note 1 is ignored.

For example, assuming speed 6, note 1 has ED06, and note 2 is placed on the very next row, using ED01 or so. Note 1 should play in the place of note 2, while note 2 gets delayed, but instead note 1 doesn't play.