פירוש על עבודה זרה 73:5

Rabbi Judah Nesi’a also made a permissive ruling in the field of divorce law. According to the mishnah, if a husband stipulates that the divorce will be valid if he does not come back in twelve months, and then he dies, the divorce seems never had time to become valid. She will be a widow and potentially subject to levirate marriage (marriage with his brother if her husband did not have children). But R. Judah Nesi’a ruled that the divorce was valid because of the date written on it. This date proves that the husband wanted it to become retroactively valid when he failed to come back. Thus when he fails to come back it is valid from the time it is written.
The other rabbis did not agree with Rabbi Judah Nesi’a. And since he had used up two of his leniencies, he did not want to risk a third.