Hey, guess what. Claims of "top secret" information in Hillary Clinton's email are, according to the intelligence officials tasked with investigating it,
untrue.
The determination came from Director of National Intelligence James Clapper’s office and concluded that the two emails did not include highly classified intelligence secrets. Concerns about the emails' classification helped trigger an on-going FBI inquiry into Clinton's private email set-up. [...]
"The initial determination was based on a flawed process," the source said. "There was an intelligence product people thought [one of the emails] was based on, but that actually postdated the email in question."
So there you go. Apparently the dispute between the State Department and the intelligence community was based on the intelligence community flagging information in one of the emails as being from a classified source, but the State Department emails were written
before the intelligence effort in question, based on other, non-secret information. It was just a flub by an overzealous reviewer.