Is the expiation for intercourse during the daytime in Ramadan obligatory for one who is already not fasting, or is it only obligatory for one who invalidated his fast by intercourse?

Intentionally breaking the fast in Ramadan (definition) is one of the major sins, and the one who breaks it must offer sincere repentance. If the one who breaks the fast did not engage in intercourse, then the prevalent opinion is that expiation (kaffara) is not obligatory upon him. However, if he did engage in intercourse, the Hanbalis are of the view that expiation is obligatory upon him, even if he had already broken his fast earlier, due to his violation of the sanctity of the time. In contrast, the Shafi'is hold that expiation is only obligatory upon one who invalidated his fast through intercourse, not upon one who engaged in intercourse during the daytime of Ramadan after having already broken his fast by other means. The opinion that expiation is obligatory is more cautious.