Hi Yoseihana,
In version 3.6 of the plugin the following was changed:
Moved all HTML Markup (and the loop) to the List Widget template
You probably have a custom template for the widget in your theme. Update the following file to fix it:
{wp-root}/wp-content/{theme-name}/tribe-events/widgets/list-widget.php
You can use this file as a starting point:
{wp-root}/wp-content/plugins/the-events-calendar/views/widgets/list-widget.php
Cheers!
Laurens