Handling of multiple MIDI tracks in one song

Previously, I had trouble with MIDI tracks affecting each other, such as pitch bending. I was advised to uncheck “Read data from tracks even if muted”, which seemed to work.

Now, in a song with several MIDI tracks, notes in the last MIDI track cut out or are not played.

All other MIDI tracks are muted.

I moved the track up above other MIDI tracks but same problem.

I exported the MIDI file and opened it with a dedicated MIDI editor. It played normally.

I copied the entire song to another folder, then removed all the other MIDI tracks. It played normally. I would rather not have to remove the other MIDI tracks, though.

Edited to add: Even without the other tracks removed, the problem track plays properly.

My question: is MIDI data (notes?) still going to the synth even though “Read data from tracks even if muted” is unchecked? If so, is there a way to turn them completely off?

I am using a Korg T2 (late 80s?) synthesizer connected through an M-Audio interface. It’s an old synth with somewhat limited polyphony. If all the MIDI tracks are sending notes, that may exceed its polyphonic capacity.