The long press back button to watch face is a neat feature to get out of a deep-level menu setting straight to watch face, typically when not in a workout.
Sadly, since I assigned a shortcut to the back button, this stopped working. Now even if I unassign the back button shortcut (i.e. set to none), doesn't work either. Only short press to go a level up.. in a deep menu, this is annoying.
There is no customization for long press of the back button, AFAIK, so seems like a bug.