Fringe theory - take it for what it is worth…
Manafort was a plant. That is fairly well established.
What if he is being "sweated" to reveal who was behind him being inserting as a plant? He might not want to reveal the true plotters for fear of his life etc.
Just for the record - I am absolutely against this form of tyranny and detention without trial and conviction. Yes i know about the witness tampering, but his treatment is outrageous.