Disable lap button during workouts


I own a fr945LTE and I want to disable the lap button completely. I can disable it in the app settings (laps -> lap button off) but the option seems to be ignored with garmin coach workout or daily suggested workouts.

This thing is pretty annoying since during workouts I often press the back button when going back from the map or the music menu. If a HR alert pops in (which can't be disabled too SIGH) exaclty while I'm pressing the button, then the workout is over.

Does the same behaviour happen in the fenix line too or is it a bug of the 945LTE?