Cannot define (or redefine) specific shortcuts (& bug)

When I go into the Preference->Shortcuts area to define the shortcuts for "Enter interval: ____th below" (which is never assigned by default in advance) it allows me to go through the motions of defining the shortcuts, but they do not work. Even after restarting the program, the new definitions are still there but do not work. One side note is that when I use (on a Mac) the shortcut, for instance, option+shift+4, instead of it being defined this way, it follows the command of the keyboard itself which does not show the 3 keys, but rather the symbol for option followed by the $ sign (because shift+4 is $). Anyway, any help would be greatly appreciated (or any news that this is not possible in MuseScore Studio 4.5.1...).