But detailed, contemporaneous documentation showing Sondland lied in his testimony does exist. Because the NSC lawyers have it.
Thanks to @AmbJohnBolton, who made sure his subordinates went in to document every step along the way, Eisenberg knows a lot.
But that's not all that Trump says. And we know this because Sondland immediately calls Morrison to tell him.
Sondland's call had a specific purpose: to update Morrison on a change of plans from what was agreed to in Warsaw. Trump rejected the Prosecutor General compromise, he wanted Zelensky.
1. In the "no QPQ" call, Trump told Sondland about the specific quid pro quo that he required from Ukraine
2. Morrison immediately informed NSC legal about the call
3. NSC legal has contemporaneous records showing Sondland's testimony about the call is false
Because the same day the call happened, Morrison ran to NSC to report it. And the NSC's Sept. 7th records are far more reliable than whatever Sondland said.
And then, in Sept, when given proof that Trump had escalated the conduct that had resulted in the criminal referral, Eisenberg kept it hidden.