Polyphonic notes dropped at random

[TheSquirrelStic]

When playing the track "NCS_BGM_VS_CASTLE" from New Super Mario Bros. Minigames (the mgvs_sound_data.sdat file), there are polyphonic notes that don't play properly (as in, one of the notes may be dropped at random). For example, at position 0x16F on the second channel, it is supposed to play both A#5 and F5 simultaneously, but one of these notes is dropped randomly unless I set the playhead to immediately before when the notes are meant to play. I have provided a video below demonstrating this.

NSMB.Minigames.Castle.Bug.mp4

Something similar also happens with the "SEQ_STAGE_SELECT_NEW" track from Mario vs. Donkey Kong: Mini-Land Mayhem!, though to a much more extreme extent (probably due to using all 16 channels).