I have the smart tray SE, and the slot on the far left doesn't seem to be doing anything. The rest of the tray works fine, but that one part doesn't seem to be dischargeing.
Also I haven't used it nearly 6 months, as I havent had the money to send it in for repairs since I bought it 4 months before it had the issue. Maybe it was just an issue with some of the first batch of tray's, or just some freak issue.