Hi,
Glad you figured it out.
With 3.10 we made some changes and the custom templates need to include this now:
In the list-widget.php template you can add these to the top and that might fix the issue instead having to redo custom work:
$events_label_plural = tribe_get_event_label_plural();
$posts = tribe_get_list_widget_events();
Since this is marked resolved I am going to close this ticket, but if you need anything else related to this topic or another please post a new topic on the forum and we can help you out.
Thanks