How bad has the .gov screwed-up the Bundy case?

This badly.
A judge declared a mistrial Wednesday in the Bunkerville standoff case involving rancher Cliven Bundy and other defendants, finding that the federal government improperly withheld evidence.

“A mistrial in this case is the most suitable and only remedy available,” U.S. District Judge Gloria Navarro said.
...
Navarro said video surveillance, maps and FBI interview information were willfully withheld by the prosecution in violation of due process required by the U.S. Constitution.

Considered collectively, she said, the evidence that was withheld was favorable to the defendants, and its untimely disclosure was prejudicial in that it “undermined the confidence of the outcome of the trial.”
About that EffingBI information,
In her ruling, Navarro cited case law that says illegal suppression of evidence occurs when the government fails to turn over information that was available not only to the prosecution, but to federal investigative agencies.

She said information and reports obtained and created by the FBI were available to prosecutors and should have been made available to the defense.
So, a new trial.  Which means, with this data, the defense is going to have a bunch of new questions for jurors, and the trial, and I'd imagine a number of the BLM and FBI clowns involved in this might find themselves on the stand and under oath, which might have some interesting results.