This issue has been resolved.
When trying to open an archived proof in the Proof Viewer, users receive the following message: "This proof has just been archived. You no longer have access to it."
This message displays when you attempt to open an archived proof after a new version has been added. The new version of the proof becomes the only accessible version.
You can workaround this issue by opening the Proof details page and unarchiving the version you want to open. For information on using the Proof details page, see "Managing Proof Details in Workfront Proof."
Our development team should have a resolution for this issue soon.