Description: When hiding a content node in the admin interface and immediatly unhiding the node again, the page outputs JSON data instead of the admin interface HTML.

Steps to reproduce:
1. Log in to admin site
2. Hide any content node in the locations tab
3. Unhide the same node again
4. Page does not show the admin interface HTML, but shows plain text JSON data

Workaround:
Refreshing the page each time in the browser between step 2 and 3, after toggling visibility

Additional notes:
Bug does not exist in v4.4