It seems that if I set a midi track to listen to the correct channel, then it will pass midi through the midi-out port.

For instance if my monomachine is down the in->thru chain and listening for auto-channel on 2, I have to set a midi track on the octatrack to channel 2 and set my keyboard to output on channel to.

Keyboard(channel 2)->Octatrack Midi-In->Midi track 2 set to channel 2->Octatrack midi-out -> Monomachine Midi-in Auto-channel 2

I will experiment with this some more, but it seems to be acceptable. I somehow missed in the manual if it explains how incoming midi notes are handled. I’ll have to try and find that again.