You say there is a midi channel being sent to 6 utility tracks?? That is odd indeed. Can you upload the .sgu/mgu file?
Regarding Utility#3. There is a new 2023 feature found in options-preferences-Output Chords. This feature will automatically write the chord chart as a midi track to Utility#3. It should be off by default, but if it is on you may hear the chart chords playing via you default synth through your song on this utility track.
Thank you for the information, I appreciate this a lot.
I did reset all BIAB settings before posting this bug report, however I double-checked Output Chords and it's definitely OFF.
BTW, I've added a How-To to my original posting, so everyone should be able to reproduce the problem.