Is my understanding correct that Sheikh Al-Isnawi holds that divorce does not occur if the one who swore intended the reality of the matter when swearing by conditional divorce related to something that has passed?

If someone swore an oath of divorce negating something in the past, based on their assumption, and it later became clear to be contrary to their assumption, and their intention was that the matter was truly so, then regarding the occurrence of his divorce according to the Shafi'i school, there are two opinions: 1. It occurs, and this was preferred by Ibn al-Salah and al-Zarkashi. 2. It does not occur, and this was preferred by al-Isnawi and others, and it is the more plausible view, because the ignorant person does not break their oath.

However, if the swearer intended that the matter was so in their assumption or according to what their knowledge had reached, and did not intend that the matter was truly so, then he does not break his oath.