Shift+Ñ seem to be the default keyboard shortcut for stop tuplet creation. But in Preferences>Keyboard shortcut the box appears empty.
If I try to insert Shift + Ñ, I get a warning:
“! Secuencia de teclas ya asignada a: NoteImput.EndTupletRun” (! Sequence of keys already assigned to: NoteImput.EndTupletRun) which seems to be precisely the function that I try to access.
Despite the warning, the shortcuts Ñ and Shift+Ñ work rightly.
Maybe this is related in some way to:
I was trying some changes in the keyboard shortcuts when I found this.