Igor Danchenko was a well-known fabricator of (dis)information long before the FBI made the purposeful decision to enlist him in their Trump targeting efforts.  Specifically because Danchenko had no moral compass to the truth he was particularly useful for the FBI effort.  This was the big problem for John Durham in prosecuting Danchenko for material lies the FBI knew from the outset were false.

How does the same DOJ who used the lies for their political purposes, then prosecute the liar for the false information?  That was always the structural flaw in any case brought by Durham.  As a result, the trial was not so much about the lying Danchenko as it was about the lying FBI and their use of Danchenko.