Assuming you're talking about the release of the bodycam, I'd guess the state either fucked up something and want to hide illegal actions, it being a part of the plea deal would be illegal since they should've mentioned it to the judge among other things. If it gets released, maybe it'll come out that it was part of the plea deal (probably via Nick).
Or they just don't like people looking over their shoulder when they're doing their job. Being scrutinized like that isn't fun, but then they took the wrong profession by working for the government.
There's a chance they're doing it because they think they have to protect the privacy of Nick, that they think that that's Nick's right, but I think it's not his right at this point and I don't think they'd go through these lengths to do that. Also with how sure Nick was that it wouldn't be released, I can only imagine they had talks before the plea deal about if it would be released.