The Centaur's racial feature "Charge" reads as follows:
If you move at least 20 feet straight toward a target and then hit it with a melee weapon attack on the same turn, roll the weapon’s damage dice twice and add them together. Once you use this ability, you can’t use it again until you finish a short or long rest. (Source of wording D&D Beyond)
From this I understand that the affected attack(s) must occur after the Charge ability is triggered, and must occur during the same turn the Charge is triggered.
But, as the title question indictes, I'm in doubt whether this wording means that the doubling of the weapons damage dice only occurs on a single attack that hits after the Charge, and if so must it then be the first attack that hits or can it be any attack that hits during that turn? Or would it affect every attack that hits after the Charge during that turn?