Currently if you have an Attachment Data macro in a page and want to export it via Space Export/Import function, the data won't be displayed after importing the XML file to the new Confluence and the rendering error will be displayed (refer to Scaffolding error.png).
This issue is because of Confluence created the imported content as new objects which means the newly added pages will have a new Page ID and the attachment files will have a new attachment ID as well (refer to Scaffolding XML data.png)
Steps to reproduce:
Create a page with Attachment Data macro
Click on Edit Content and upload an attachment file and save
Generate a Space backup that contains the page above
Import the Space backup to a new Confluence instance
On the new Confluence instance, the selected Attachment Data is not displayed/missing because the new Confluence instance cannot recognize the <contentId> and <attachmentId> from the previous Confluence instance.
Hosting platform | Server, Data Center |