Hi there,
My head unit is on the latest beta firmware, 12.07.
I've changed the left-side buttons so that the big button changes gears up and down, and the small button is connected to the Edge 1050, with a single button press ringing the bell.
The problem is that when adjusting the front derailleur, even though Garmin understands I'm adjusting it, pressing the small button adjusts the derailleur and rings the bell simultaneously.
I hope this can be fixed in the next update to override the button settings during derailleur adjustments.