Back on topic some things have become more clear.
Remember the indictment alleges that Comey lied about "authorizing" someone "at the FBI" to "leak anonymously."
There was some question about who that someone could be. One speculation was Chris Wray, who apparently did leak anonymously, but even according to his testimony to Congress and elsewhere, did so without Comey's prior knowledge or approval.
The other person was Daniel Richman, a professor at Columbia, with whom Comey communicated about various things as a friend and consiglieri. And Richman was in fairly constant contact with the press, but rarely, if ever, anonymously.
And Richman was not an FBI employee, fairly obviously.
He was, however, a "special employee" uncompensated consultant for the FBI. But the terms of his "employment" are murky and it appears that he was not actually so employed in the relevant timeframe.
https://www.lawfaremedia.org/article/more-trouble-for-the-comey-indictment
Another hole in the government's already flimsy case.
The most glaring problem with the case is that what Comey said to Congress, within the limitations period, was "I stand by my earlier testimony." And that is a statement that is not really capable of being proven false. Certainly not by proving 2017 testimony false.