Yeah, there is no way that counts as perjury. The question asks for a legal conclusion, not a fact, and for good reasons we make it very hard for anyone to call perjury in strained conclusions. In a real case, you wouldn’t just have to admit “oops an agent screwed up.” You’d have to give some sort of contextual information about the process the agent was supposed to be following, and how he deviated. There is a colorable argument that this could result in some disclosure of importance to national security. Just because it’s a stupid argument and the judge didn’t buy it doesn’t mean it’s perjury.

The government got the correct sanction here, a finding of “bad faith” and attorneys’ fees, which is what courts do when parties push thin legal arguments further than they should.