Those who thought that the prayer was shortened when the Prophet (peace and blessings be upon him) prayed two rak'ahs in the 'Asr prayer: Is their prayer complete?

The questioner : Shaykh, regarding the issue of the hurried ones: a man left the mosque and learned that he had shortened the prayer. Did he...

The Shaykh : No, he was not aware; he assumed it was so.

The questioner : He left having shortened the prayer. Is the prayer complete or...?

The Shaykh : This has been a point of difficulty for some people. Did those who left return? Or did they remain as they were? Or were they told to repeat their prayer, and they did? All of this is possible. It is possible that they returned when they heard the takbir, or when they saw the congregation delaying and slowing down, they returned. It is possible that they were told later to complete their prayer because the prayer was not valid or complete. It is possible that they remained with what they prayed and did not complete the prayer. So these are three possibilities, is that not so?
If it is so, we return to the principle that the conscience is not cleared except by a complete prayer. So this text or this hadith remains ambiguous and confusing. The legal rule is that when there is ambiguity, we return to the clear text that has no ambiguity. So if such a thing happens, and the hurried ones leave, and then...
The people discuss among themselves and learn that they shortened the prayer and completed it. We tell the imam: if you know any of them, inform him so that he prays. Otherwise, when the next prayer comes, alert the congregation. Tell them that our previous prayer was incomplete, so that they pray again. Yes.