I don't know. Maybe.
A prosecutor makes a mistake. There's a grand juror who finds out she's not going to get paid for her time, so she asks to be excused, and the prosecutor says okay and excuses her.
That's wrong. The prosecutor can't do that. Only a judge can. (Of course, there's no judge there at the time, which is why the prosecutor thought it was his job. Even though it's not.)
So the question is whether that requires dismissal of the indictment.
The Court of Appeal says it does, because having the prosecutor be the one who dismisses the grand juror makes it look like the prosecutor is controlling everything and the grand jury might accordingly be beholden to him.
Hmmm. Maybe. Though I suspect that's not what most of the grand jurors think. At all. The basic structure of the grand jury already gives the prosecutor a "lead" function, at least perceptually. When you're dealing with what seems like a routine thing -- a hardship request -- I doubt whether the grand jurors think that having the prosecutor say "That's fine, you're excused" is anything more than a pure administrative function. I'm not sure it really makes the grand jury think that the prosecutor is totally in charge, or akin to a judge. Or at least not more than the preexisting fact that the prosecutor is the only key government official that the grand jury typically sees on any given day.
So, yeah, a mistake definitely transpired. But it was an honest mistake, and one that I'm not certain really mattered at all. Particularly since there were still 18 grand jurors left, and it only took 12 to return an indictment.
So maybe the grand jury was really swayed by what transpired here.
But I tend to doubt it.