Empty can mean 

• No Configuration Applied: The page configuration record has been created but no actual configuration settings (e.g., custom fields, visibility rules, default values, or UI tweaks) have been defined or saved for that specific page. Essentially, it's a placeholder record with no active changes to the default page behavior.
• Incomplete or Unsaved Changes: If someone started configuring the page (e.g., via the Page Designer or Configuration Assistant) but didn't finalize or save the changes, the status remains "Empty" because no configuration data is committed.
• Default/Initial State: For newly created page configurations, the status defaults to "Empty" until you actively add configuration elements like custom fields, layouts, or conditions and save them.
• Configuration Not Deployed: In some cases, particularly in multi-tenant or remote deployments, the configuration might exist but hasn't been deployed to the environment you're viewing, so it appears as "Empty" in the UI.

Since it was in another instance, I’d probably go back to the page, redo the export, and make sure all the pieces exist.  Also make sure the projection has been added to the right security role.