When you copy an object from a project drawing to a review drawing and then start a Drawing Compare session, you would expect that the copied object would be identified as unchanged. However, the copied object is identified as new and missing.
This is because Drawing Compare uses object handles to match objects in review drawings to objects in the project drawings. When an object is copied from one drawing to another, it is assigned a new object handle and is identified as a new version of the object. This results in the object being identified as missing in the project drawing and new in the review drawing.