question on bulkhead connector bypass

It is telling you exactly what I told you earlier. There is VOLTAGE DROP in the path from the battery, through all the harness and connections that is dropping the sense voltage to the VR IGN terminal. The drop is likely not "stable" that is, it "arcs across" and changes resistance.

Just what is it that you are using to read this board?

..........and this is the reason some guys install a relay to allow the relay to supply a more direct and more stable, less drop path from the battery to the VR.