Without downloading the song,
When looking at the image, i also see there are effect-command related options to this fader, but that might be the c00 command that you attempted?
There is a difference between channel volume (03xx) and track volume (0cxx).
What can be a nuisance is when you set your fader to a certain position in the start-pattern and you save your song, then that is the initial value the song starts with. A 0c80 on row 00 of your first pattern in the song should at least set the fader to 0db.
Download the song, remove all the commands, try to get the pre-volume to do something. It’s broken, and only on that track. I’m guessing something odd in the XML that Renoise needs to be aware of as this is a “dead-lock” situation.
The first device in the chain (the one which controls the pre vol/pan) somehow got bypassed. I dont know how you manged to do this, as this can not be done in the GUI and not with automations, but if you send the song over to me (taktik renoise com) I will repair it for you.