Is it permissible for a traveler to pray two rak'ahs behind a resident imam and not complete the prayer with him?

The questioner : A man prayed the 'Asr prayer, and then two men came behind him and prayed with him while he was completing the 'Asr prayer. When he stood up from the first tashahhud, the two men sat down until he completed the two rak'ahs, and then he said the taslim, and they said the taslim with him. What is the ruling on their prayer?

The Shaykh : Meaning that they are travelers.

The questioner : Yes.

The Shaykh : Their prayer is not valid. Tell them: They must repeat the prayer, because if a traveler prays behind someone who completes the prayer, he is obligated to complete it. The evidence is the saying of the Prophet (peace and blessings be upon him and his family): And this is a matter on which the imam differed without an excuse, so they must repeat the prayer. It should be known that if a traveler catches up with a rak'ah of the one who is praying four rak'ahs, whether he catches up with a rak'ah or less, even in the final tashahhud, he is obligated to complete the prayer, due to the generality of the saying of the Prophet (peace and blessings be upon him and his family): .