To me that part is pretty weak compared to the security disclosures. The "lie" is about whether or not Twitter executives are incentivized to delete bots (later on he says that Twitter is incentivized to keep bots out of mDAU because they don't click on ads so they'd tank the clickthrough rate, kind of blows a whole in Elon Musk's whole thing). In reality I'm sure there are multiple overlapping and contradictory incentives at play, but it's not really a falsifiable statement so not really something you can "lie" about.
The way it's framed ("Twitter lied to Elon Musk about bots") makes me suspicious of the whistleblowers' motives here. I know he's some kind of legend around these parts but I've never heard of him, so I'm just going by what I've learned today. Seems like propaganda to me, intended to maximally damage twitter and/or curry favor with Musk.