I've been pouring over all the wiring diagrams trying to help you out here and the only scenario I can come up with is that the power feed to the coils and other circuits is being fed through the starter interlock switch when you are using the new European handle bar switch so you need to figure out why this is happening with the new European switch. I'm just wondering if something funky is going on with the wire coloring.
Some tests to do please to confirm that the wires with the color codes are correct.
Test leads coming from the handlebar switch
Test resistance between the yellow wire/red stripe and the brown wire. should be 0 resistance with the switch in "Run" position and open circuit in the "Off" position.
Test resistance between the blue wire/red stripe and the black wire. Should be 0 resistance when the starter button is pushed and open circuit when the button is not pushed.
The blue wire and the brown wire /white stripe coming from the headlight switch are tied back and isolated from touching anything correct? Since the headlight switch takes a power feed from the brown wire coming from the ignition switch