An object may go through several approval cycles before it gets published. For instance, in a serial approval cycle, the second approver might have noticed an error that the first approver did not spot, and will reject the changes. Alternatively, an object may have passed an approval cycle, but underwent modifications before its publication, triggering another approval cycle. In both of these scenarios, the approver might not remember what they have approved if there were several cycles between the approved/rejected change and the publication.
To compare changes since your last review of the object, follow these steps:
1. Make sure that you have approved or rejected a change on an object at least once.
2. Within the details tab of the document, expand the approval cycle box and click on Show Changes Since My Last Approval. Elements that were added will be highlighted in green, and elements that were deleted will be highlighted in red.