Two concerning quotes from that article, seems likely deliberate delaying until after the election to me
"There are folks that are aware of the fact that Huber has not done much, and there has been criticism at the Justice Department and the White House," the source said. "Folks that have been concerned about what he did or didn't do, and many of them feel that Huber did not dig deep enough or work hard enough."
"The source also told Fox News that Durham “does not want this to be viewed political,” and the closer it gets to November, Durham could “punt it to after the election.”