The Duty of One Who Doubts in Recommended Prayers
Issue No. 1074 - In recommended prayers; one should act, as an obligatory precaution, upon his own presumption, so far that it does not invalidate the prayer. For example, if he presumes that he has offered two rak‘ats, he should pay heed to that probability, and if he presumes that he has offered three rak‘ats, he should consider himself offered only two rak‘ats.
