CoursePress appearrance customization has js error

Greetings,
After updating Wordpress to 4.5, there is now a javascript error on the theme customization page when the CoursePress theme is chosen. I am not able to customize any of the settings for the appearance:

TypeError: data.defaultValue.substring is not a function
 /wp-admin/load-scripts.php?c=1&load%5B%5D=underscore,customize-base,wp-a11y,customize-controls,backbone,wp-util,wp-backbone,customize-widgets,jquery-ui-button,jquery-ui-s&load%5B%5D=pinner,jquery-ui-t....

You have access to the site. Thanks!