You notice an offset between the file system Modified Date property of a document and the Modified date shown in eDiscovery Bundle Legal Review.
Legal Review normalizes the Modified date to UTC timezone.
This behavior is by design and this is required to ease the review process when documents are extracted from multiple machines. Consider that documents for the same Legal Matter could be extracted from machines that have different localization settings. In this case, Legal Review helps the reviewer by normalizing the dates to UTC for all documents.
3.1; 3.2; 3.3; 3.4; 3.5; 3.6; 3.7