I specifically remember writing a clause in the AA rule stating that one has to reuse the original die roll if redoing steps in an AA.

That is correct, but I don’t believe the clause applies if the Atomic Action was not started in the first place (ie, if the die was rolled before the first action was taken). Here is the rule which your die roll clause modifies:

“If one or more steps of an Atomic Action were done incorrectly, the Adventurer must redo the Atomic Action. In redoing an Atomic Action, the Adventurer uses any legal steps that were already completed in the illegal Atomic Action and only redoes the illegal ones.”

But this rule did not hold me, as I don’t believe I can have “done a step incorrectly” if I have not yet arrived at that step.

(The specific example presented in the clause you refer to applies even less.)

I might as well recite that clause, here, too:

“For instance if an Atomic Action consists of rolling a die and then doing steps based upon its result the Adventurer would have to reroll the die if they rolled the wrong one if the first place and any steps that depended upon the result of that die; however if all they did was take an illegal action later on, the die is still used in the redone action.”

Didn’t take an illegal action “later on”. I just rolled at the wrong time.

So it boils down to whether or not I really started the AA when I rolled a die for it’s second step.

I suppose you rolled it out of order, which I think would be just like rolling a die for fun? It’s not that important for the dynasty.

I agree with TyGuy’s assessment here. Still, I still don’t like how a Battle starts with resetting the stats from the previous Battle, and it turns out to be confusing, so I’ll try to change it.

(At some point I’ll aim to improve the wording of the second clause TyGuy recites above, which is not entirely clear.)