It's a shame the game has no check for this as that would allow the same menu to be used by a character you get later without bugs.
I don't suppose there is a way to extend the number of available magic menus? you'd think there are plenty but i had some "skills" in mind for characters like cid etc but i am already having to make Tellah, Golbez, and FuSoYa share the exact same white and black menus as well as sacrifice Edge's menu to a more useful magic user.