Does the expiation of one who fed the poor, believing it permissible to choose feeding over fasting, then learned of the obligation of continuous fasting as expiation for breaking the Ramadan fast by intercourse, become nullified?

The majority of scholars hold that the expiation for intercourse is on a sequential basis: freeing a slave, and if unable, then fasting for two consecutive months, and if unable, then feeding sixty poor people. The Malikis, and one narration from the Hanbalis, are of the view that there is a choice between these three options. So, if a person has fed the poor, the expiation has been fulfilled for him; because he has acted in accordance with a respected view of some scholars, and an ordinary Muslim is permitted to follow someone whose knowledge and piety he trusts.