When Content is added into block inside Landing Page (for example: in Content List block) then Landing Page and Content is deleted and only Landing Page is then restored may result in a broken Page Builder.

Steps to reproduce
1. Clean installation of eZ Platform 2.5+
2. In Home create a folder Folder and publish it
3. In Home create a new Landding Page Landing Page. Add a Content List block and add Folder to it. Publish Landing Page.
4. From the Content Structure view select both Folder and Landing Page and send them to Trash
5. Delete Folder from Trash, then restore Landing Page.
6. In Content View select Landing Page and click edit.

Result
In prod environment:
Page Builder will display Landing Page in edit mode, but with empty Content List block. Clicking on Publish will publish the page. Attempt on changing Content List block options will break the Page Builder.

In dev environment:
Page Builder won't start in edit mode. Switching to preview will throw an exception:

An exception has been thrown during the rendering of a template ("Could not find 'Content' with identifier '58'").

Expected Result
Page Builder working normally. Empty blocks showing errors on publish attempt.