Overview:
Linked annotations are missing the linked document hyperlink after bringing the annotations forward to a new document version.
Root Cause:
The user, who brought over the annotations to the new document version, does not have permission to view the documents linked in the annotation.
Solution:
Be sure the user that brings over the annotations to the new document version has the correct access to view the documents linked in the annotation.
Related Documentation:
Vault Annotations Documentation: Bringing Forward Annotations