It obviously means Manafort is not giving Mueller the desired cooperation. Either they think he lied when getting the deal or has lied since. I suspect Manafort’s version is that they want him to lie and he won’t do it.
That goes without saying but still doesn’t come close to getting to the crux of my lack of understanding. Why has Mueller chosen to announce this. Did Manafort ever cooperate or did he not and never intend to? And if he never intended to, why enter into a plea agreement.
What I’m saying is a whole lot of it does not make sense and Mueller has a tough road to hoe proving Manafort lies and having to prove it now that he has announced it.