I have a very customized vim configuration, but I don't think it has anything to do with this, because nothing has changed the key binding system.
When I press
g I can leave the window there and make a sandwich and come back and it's still shown in the part of my statusbar that shows pending keystrokes (I forget what that is called).
But when I press
<Leader>) it times out and beeps after one second.
When I check maps, I see that neither
\ have primary mappings to just that key (which would indeed cause them to trigger their mapping upon timeout or receiving another non-matching key).
So what then is the difference between these two cases? Why doesn't
\ leave me more time, or, why does
g not time out?