I don't do scans too often on the CMS interface but only when I update the app, recently i've updated to the last version and when I did a full scan it started very slow previous version wasn't that slow. Also the notification while scanning disapears when I put the app on background and if I close the app it stops the scanning, my device is a S4 with kitkat 4.4.2. I'm gonna back to the previous version and see if this behaviour stills, later...