Document security, management and tracking is one of the largest liabilities facing organizations. Case in point, is when a law firm has to share information with another firm. That's called "discovery".
Before one side shares with the other, specific aspects of the case are commonly redacted in an attempt to protect their client. Redaction may include images, license plates, birthdates, social security, credit card or statements from either plaintiff or defendant that could be construed as damning to the case if exposed or submitted accidentally.
Sharing those documents doesn't stop between the two firms. There's a third party who must see the unredacted version. That person is a judge.
Now we have three parties involved with two master copies, two redacted copies and one unredacted copy in play. A total of five documents, any one of which is potentially a free-floating liability if exposed due to ransomware, malware, or carelessness.