The ruling on one who combined two prayers and then arrived in a town during the time of the second

Question:
A group traveled from Riyadh to Dammam, and they prayed Maghrib and 'Isha' in Dammam, combining them by advancing them into the time of Maghrib. Then they boarded a plane heading toward the west, and the plane landed for them in a town in the west, where they found that the sun had not yet set. Is it obligatory for them to pray Maghrib and 'Isha' again?

Answer:
That is the apparent ruling; because they are now in a town where the time for prayer has entered, they are required to pray. The sun set while they were in the town, so they pray Maghrib and 'Isha' as if they were on two separate days.
Q: And the first prayer is not sufficient?
A: Yes, it is not sufficient. This is an obligatory matter that arose due to the travel.