There is a very usefull widget named Mini Loops. But when cloning this widget to Widget Wrangler some defaults of the widget settings get lost. In this case, these are the checkboxes 'Unstick sticky posts?' and 'If viewing a single post, exclude it?' which are enabled by default.
As the widget configuration of Mini Loops also contains some HTML this will not displayed properly in the Advanced Help meta box (WP_Widget $instance). The HTML configured in Mini Loops is not escaped and thus executed when displayed.