Users will rarely do this on purpose, but they may do this by accident. If that is the case for your use, please see the SR "Locate a course that was on my current training" 

To hide a course that is in your current training, please go to your Home Page and locate your ‘Current Training’ tile. After you locate the title of the course you’d like to hide, please click on the drop-down arrow to the right of the course beside the ‘Resume’ button and then click on ‘Hide’ from the menu that appears. Then choose 'Yes'.