Does the saying of Sheikh Abu Zayd al-Marwazi, that whoever is deficient in reciting Al-Fatiha due to preoccupation must make it up before following the Imam, apply to preoccupation before starting the prayer or after it?

Al-Marwazi's discourse concerns one who, upon initiating prayer (takbirat al-ihram (definition)), becomes preoccupied with the opening supplication (du'a al-istiftah) and seeking refuge (ta'awwudh) instead of reciting Al-Fatiha. If the imam bows while this person is still engaged in these, then it becomes obligatory upon him to recite from Al-Fatiha an amount equivalent to the time he spent in preoccupation. The correct view, however, is that if he did not utter any part of the opening supplication or seeking refuge, he should bow, and the remainder of Al-Fatiha is waived for him. But if he did utter any of that, then it is obligatory for him to recite from Al-Fatiha an amount equivalent to what he uttered, due to his shortcoming in becoming preoccupied.