Yes / No buttons not displayed in Subscribed column on forum index page

Add the activities block to a course Create several forums, including some with types: Standard Auto Standard Subscription disabled Standard Force Standard Optional Single Simple Discussion Auto Single Simple Discussion Disabled Single Simple Discussion Force Single Simple Discussion Optional Login as a student View the course and click on 'forums' in the activities block Confirm that you are able to subscribe and unsubscribe from all of the forums except for those which have have subscription forced or disabled