There's a reason why, and I've checked this recently with the dungeon updates: In general, you have a longer cutscene than anyone else if you're a new player. Since this is our first encounter with Lahabrea, we need to fix this.

I actually had a party that killed Graffias faster than I could go through the cutscene at a normal pace, letting the voice lines play out since it's a voiced scene. In order to prevent this, if one player has not cleared Totorak and the additional reward is available for clearing first time, force the Lahabrea cutscene on other players and do it like you used to do Castrum and Praetorium.