The rng 'die rolls' are set your first attempt, so if you don't change anything such as using an aoe instead of basic, it will remain the same. Change your actions, adjust your team. This will cause rng to reset. I've used this to my advantage too, where I would get a few good rolls then a miss, so I go back in, replay up to that point, then change the action that missed. Not sure why they designed it this way, but knowing how it works you can use it to your advantage.