Sure. I mean, a clever enough fix is unavoidable. Like, suppose I swapped out all the machinery with duplicates that had different vote counts but matching ballots. If a back room was cranking them out in parallel, the total votes cast and even timestamps (if there are any) would match.

But we can set the confidence we want and test enough ballots to get there. In this past election, some states decided it was "100% sure to this kind of detectable attack" and they hand counted every ballot.