To turn the headlight off you need the ignition on but engine not running.
1) Press RH indicator button for 5 secs.
2) Press cancel button for 5 secs.
3) Start the bike.
Unless you're turning the bike round with the ignition on and accidentally pressing the switches [tank-bag etc] I don't see how it would happen.
Do you get a warning on the dashboard?
Switching the ignition off resets to the normal headlight on mode, on re-start.
Well its looks like you can turn them off accidently, but fortunately you do get a warning on the dash which is the same as a blown bulb warning. They have come back on again now phew!!