Comey had more than one memo, and the contents of one of the memos (not the "drop Flynn investigation" order memo) was published on May 11.
Comey leaked before the "tape hope" tweet. You might argue over what he leaked before, but no question he leaked before.
Is it possible ... just possible ... that the NYT did not have any memo for the May 11 article and that the source was an interview with Comey himself?