bbPress.org

I seem to have an error with the page previews as you can see over here. As you can see in the first reply in this link, page preview for WP pages works fine, the problem only occurs with BBpress related urls (second post). In the image below I marked it with red:

When I disable the GP Premium plugin the preview dissapears and it only shows the title as an url inside a blockquote. BUT looking at the source code the wrong preview is still there. Changing class wp-embedded-content position: absolute; to position: relative; makes it visable again.

Disabling all plugins, switching to another theme or deleting all custom css is of no influence. WordPress and all plugins are up to date.