Cannot remove Favourites of Blogs and Personal Spaces

Symptom

Favourites of Blogs and Personal Spaces cannot be removed in /users/viewmyfavourites.action page as attached.

Steps to reproduce

1. Install Confluence Server 5.6.5
2. Create a blog and a personal space
3. Add them to favourite
4. Go to /users/viewmyfavourites.action page and click the stars to remove them from favourite

Workaround

Those pages can be removed from favourite on Dashboard.

Diagnosis

No exceptions are thrown on server side but Javascript's TypeError is raised on client side (See attached JavascriptError.jpg)