Doubt regarding the number of rak'ahs after completing the prayer

The questioner:
Peace be upon you. The questioner says: I prayed 'Asr, and after the prayer I doubted whether I had one rak'ah remaining or not. Knowing that I entered the prayer while the imam was in the second rak'ah, and I doubt whether I performed the fourth rak'ah or said the taslim before it, what is the ruling?

The Shaykh:
He entered with the imam after missing one rak'ah, and then?

The questioner:
He says: I doubted whether I said the taslim before the fourth rak'ah, or whether I completed the fourth rak'ah?

The Shaykh:
Meaning, he doubts whether he performed the fourth rak'ah after the imam's taslim, or whether he did not perform it?

The questioner:
By Allah, the question is clear.

The Shaykh:
If the doubt occurs while he is in the middle of the prayer, he relies on the fact that he did not perform it; he builds on certainty, stands up, and performs a rak'ah. But if the doubt did not arise until after he had exited the prayer and the prayer was finished, then doubt after the act of worship is not forgiven; it is not heeded. Yes.

The presenter:
May Allah reward you,