Reading that story a little more carefully, I'm not sure it's wholly accurate.
The AUSA said the other day it was "his understanding" that the second indictment was not presented to the full grand jury.
In a written filing, they worded it a bit more "cagily."
Also, before we get too excited about this resulting in dismissal of all charges (there are several other things that could have that result), there's a case that some have trumpeted as being on point. Many years ago, the DC grand juries weren't presented with indictments, just the evidence and "returned" a piece of paper saying they true-billed or no-billed a charge of a crime, ie wire fraud or perjury or whatever. The US Attorney then prepared an actual indictment in the form we see that was never actually passed on by the grand jury.
The DC Circuit ruled that that did not satisfy Rule 6 and the requirement that the grand jury be presented with and pass upon an indictment. It requires an actual indictment, and the indictment that is filed to commence a criminal case. It also held that that was harmless error in that case, so no harm no foul.
That means that the government will probably continue to be embarrassed and debase itself on Comey's other motions.