According to the section of the manual (pages 111 to 112) about the MIDI sequencer:
HOW MIDI IS ROUTED
If an audio track and a MIDI track share the same MIDI channel, … the audio track will block the MIDI track from receiving data.
From the section of the manual (page 44) about the TRIG CHANNEL settings:
To avoid unwanted MIDI conflicts when controlling external instruments with the Octatrack MIDI sequencer, the MIDI channels assigned to the audio tracks should preferably not be the same as those assigned to the MIDI tracks.
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