Maybe that will help for someone as workaround or smth. If you bind for switching keyboard layout to [left-ctrl] + [left-shift] than only [left-ctrl] + [any-shift] would not work. While [any-shift] + [right-ctrl] still works _IF_ you press [shift] first. And if you press keys in such order it, in fact, doesn't switch keyboard.
Maybe that will help for someone as workaround or smth. If you bind for switching keyboard layout to [left-ctrl] + [left-shift] than only [left-ctrl] + [any-shift] would not work. While [any-shift] + [right-ctrl] still works _IF_ you press [shift] first. And if you press keys in such order it, in fact, doesn't switch keyboard.