I recently watched the 2017 Laura Poitras documentary, Risk, which covers some of the time running up to the election. There's a scene in which Julian, in a candid moment, realizing that Trump is a contender/the candidate (I can't remember which at the time), laments the fact that he doesn't have anything on him. That's not to say that he didn't receive anything after that time, but one possibility is that Julian didn't have anything to release. Hard to prove either way.