You're mistaken--Smith's team in court filings did argue that it did not matter. But of course is up to the judge to decide if it is a meaningful error...and by meaningful I mean does it call into question the authenticity of of the documents in question.

Is there a requirement for document custody that has been violated by the this "meaningful error"?

That was my question. I don't know or question the documents at this time. I am asking what the requirements are.