Is إعادة (repeating the prayer) obligatory for someone who completed the prayer in Mina due to not being convinced that it is considered travel, or due to not knowing the permissibility of shortening the prayer there, or due to doubt about that? And if he shortened some prayers, does he have to repeat them as four rak’ahs? And if he completed some of them, is it obligatory to repeat them as shortened or complete while he is residing in his home country?

It is sunnah for the pilgrim who is not a resident of Mina to shorten the prayer in Mina on the eighth day, the days of Tashreeq, and the tenth day. This is the preponderant and authoritative view among us, and the Prophet, peace and blessings be upon him, and many Companions and Tabi'een did so.

The jurists differed on whether the Prophet's shortening of the prayer in Mina was due to the rituals of Hajj or due to travel.

Sheikh Al-Islam Ibn Taymiyyah said: "It is not permissible to shorten the prayer in Arafat, Muzdalifah, Mina, and during the days of Tashreeq except for the traveler, according to most jurists such as Al-Shafi'i and Ahmad. However, Malik and groups from the people of Madinah and others held that the shortening there is for the sake of the rituals, and that the Makkans and others should shorten their prayers."

The argument in favor of this view is that the Prophet, peace and blessings be upon him, did not order the Makkans to perform the full prayer in Mina, Arafat, and Muzdalifah, as he ordered them to do so in Makkah.

Whoever performs the full prayer, their prayer is valid and they are not required to repeat it.

Prayer is shortened in Mina and not combined, because that is the Sunnah. The Prophet, peace and blessings be upon him, shortened the prayer in Mina and did not combine it. There is no necessary correlation between combining and shortening prayers during travel, for shortening is Sunnah and combining is a concession.