About a year ago, a big law firm defending a product liability case found itself overwhelmed in a large document review that mushroomed into something much larger than anticipated. The firm assigned more reviewers, including an inexperienced younger associate we'll call Max. Sadly, Max failed to flag as privileged a document that clearly was. Even worse, Max was under-supervised, so nobody up the chain caught it.
The document Max failed to flag privileged, of course, got produced. (The documents in this part of the review appear to have been paper-source, because they are described as having been OCR'd, and some had marginal handwritten notes.)