When a user marks a notification as read, there is no visual indication it has been marked as read.
the only time the notification appears as read is until the next time the notification timer gets reload the data and then its marked as read.

additionally, I can multiple times try to set it as read (as the ui doesnt change I though the api call did not execute), in the logs you can see its being triggered multiple times:

 Started PUT "/notification_recipients/1" for 10.35.3.218 at 2017-03-09 12:52:47 +0000
 Processing by NotificationRecipientsController#update as JSON
   Parameters: {"seen"=>true, "id"=>"1", "notification_recipient"=>{"seen"=>true}}
 Completed 200 OK in 14ms (Views: 0.4ms | ActiveRecord: 2.5ms)
 Started PUT "/notification_recipients/1" for 10.35.3.218 at 2017-03-09 12:52:48 +0000
 Processing by NotificationRecipientsController#update as JSON
   Parameters: {"seen"=>true, "id"=>"1", "notification_recipient"=>{"seen"=>true}}
 Completed 200 OK in 14ms (Views: 0.4ms | ActiveRecord: 2.5ms)
 Started PUT "/notification_recipients/1" for 10.35.3.218 at 2017-03-09 12:52:48 +0000
 Processing by NotificationRecipientsController#update as JSON
   Parameters: {"seen"=>true, "id"=>"1", "notification_recipient"=>{"seen"=>true}}
 Completed 200 OK in 14ms (Views: 0.4ms | ActiveRecord: 2.5ms)
 Started PUT "/notification_recipients/1" for 10.35.3.218 at 2017-03-09 12:52:51 +0000
 Processing by NotificationRecipientsController#update as JSON
   Parameters: {"seen"=>true, "id"=>"1", "notification_recipient"=>{"seen"=>true}}
 Completed 200 OK in 14ms (Views: 0.5ms | ActiveRecord: 2.5ms)
 Started PUT "/notification_recipients/1" for 10.35.3.218 at 2017-03-09 12:52:51 +0000