Attachement empty after page rollback

Step to reproduce:

• Create a clean XWiki instance on 17.10.13
• Go on the macro doc page at the URL: http://localhost:8080/xwiki/bin/view/Help/Macros/
• Go on attachement and see the attachement size
• Go on History and rollback to version "Help Application 17.10.13"
• Go back to the attachement page

Expected:

All attachement have some content (size >0)
The diff between the page provided by the extension and the current version is empty (as we did a rollback we expect no diff)

Currently

All attachement are empty
The size of each attachement changed from some size to 0.