I found a bug with the new Cura 4.7 where using dual nozzles, regardless of what is selected in the build plate adhesion section, it does not change what nozzle is being called to extrude. With having extruder 2 selected, it still called on extruder 1. When selecting extruder 1, my custom start gcode is run. Not sure what is going on with this since the preview option shows the correct extruder being called.