The content will disappear or revert to the last stored version without any warning if you add a related object and any of the attributes is not validated.

Tested in eZ publish 3.8.6 and trunk.

Steps to reproduce

For a standard installation:

• Create a new article.
• Add some content in all fields, and f.ex: in the intro, add a text <bogustag>
• Press the "Add Object" button in the related image attribute.
• Select an image and press select.

When you're getting back to the article, all content that you added in the first place is gone.