The police threatened Amanda with prison time and cuffed her. The "translator" suggested that Amanda was repressing the memory of what actually happened. The blame for why Amanda's statements on that night make no sense lies squarely with the investigators. Amanda recovered her memory of what happened by the time that she wrote the second memoriale of 7 November and the letter to her lawyer, perhaps a day or two later.
The Norfolk Four were navy guys, yet they gave false confessions. One man who gave a false confession was intelligent and motivated enough to get into law school later an become a lawyer. I would not ever underestimate what level of intimidation some interrogators can achieve. In the case of PM Mignini, we have Doug Preston's viewpoint, among others that we can use to base an opinion of his tactics.
We know that even when Knox recovered her funny memory, she still remembered Patrick murdering Meredith. She has been convicted for providing that false testimony because she was guilty of implicating an innocent man for murder. That is a very serious offense, one that is inexcusable ... especially from someone that has wiggled out of a murder conviction.