Oh, and because it's a classified mission, we don't even know if the mission was INTENDED to stay in orbit. For all we know, it was a test of a reentry vehicle of some type. Additionally, off-the-record sources may just as well be lying about the result of the mission as they would be risking jailtime to leak results to reporters. This is a classified mission, no one is going to risk their job and their freedom just to make Andy Pasztor better able to troll SpaceX (which he has a long history of).
They may even be paid to intentionally spread misinformation (anonymously, so it can't be traced back) about the mission in order to protect the secrecy of the payload.
Additionally, SpaceX is continuing Falcon Heavy processing without skipping a beat, rolling out the vehicle just hours after mission completion. If there was a failure, there would be a stand-down to determine the cause before continuing.
. .
EDIT: I should point out that Northrop actually provided the payload adapter and handled integration: https://forum.nasaspaceflight.com/index.php?topic=43976.msg1...