And it therefore infers, if not asserts that Mueller has been too busy trying to take down the Trump administration, to even take the appropriate time to validate whether his witnesses and their evidence was even sound to begin with. And therefore it may even require a new special prosecutor to evaluate the soundness of the the current one, if not his removal completely. If nothing else, Mueller's free wheeling days are reaching an end, as he's facing a true legal attack on his rear flank.
Mueller, if he has any integrity or honesty, already realizes that the "crimes" allegedly committed by Trump are actually crimes that were committed against Trump. And that some of the anti-Trump conspirators, i.e. Strzok, were part of his investigation team. Mueller must now make a decision: either he can go down with the anti-Trump criminals his investigation was created to protect, or he can confess that he has been used by these people for unethical purposes and become a witness against them. We'll soon find out which road Mueller wants to travel.