What is the ruling on one who doubts during the prostration of forgetfulness whether he performed one prostration or two, and then salam-ed from the prayer due to not knowing what to do?

If a worshipper doubts whether he performed one prostration of forgetfulness (sujud as-sahw) or two, he should assume the lesser number and perform another prostration. If he does not do so before the salām, his sujud as-sahw is incomplete. Scholars differed regarding whether the prayer becomes invalid due to this. The most preponderant opinion is that it does not invalidate the prayer, based on the principle that sujud as-sahw is a sunnah, or that obligatory acts are waived due to ignorance. If he intentionally abandoned sujud as-sahw, his prayer is invalid. If it was due to forgetfulness or ignorance, his prayer is valid. If, in this case, sujud as-sahw is something whose omission does not invalidate the prayer, then there is no issue with the prayer's validity. However, if it is something that, according to some scholars, invalidates the prayer by its omission, then it is more cautious to repeat the prayer to avoid scholarly disagreement.