It means evidence backing up Greenwald's controversial position was still not checked out. The fact that the centerpiece of a story could be "lost" before it was even studied would show that Greenwald was jumping the gun.

He has no access to the evidence but he is making very preliminary bets.

Greenwald doesn't work for Fox and there are multiple copies of the documents, I don't see your point?

News agencies outside of Fox / NY Post haven't been able to study the evidence on a developing story, and Tucker Carlson has yet to reveal critical evidence.

Glenn Greenwald's own editor is telling him not to make preliminary bets. What's so surprising here?

i think what greenwald is basing is story on is all in the public domain. i think tucker is prone to hyping stuff so these documents probably don't add much.