Stuttering and ends of y axis

My mini has started stuttering at both ends of the y-axis. It still prints fine but when it homes to either end of the y-axis it intermittently stutters (sometimes quite a bit). The tray moves smoothly and there is nothing blocking the travel. I checked the y-axis switches and they seem to work fine and there is no debris or anything. The belt appears fine and it is still printing accurately. Any ideas what is causing this?

Check the small setscrew on the Y motor pulley?