I am using The Events Calendar on http://bcap.org. The Events List Widget is used in the sidebar on the home page as well as other pages.
The View All Events link in the widget goes to:
This link often displays a 404 error and sometimes does not. It is random and in the same day can show the upcoming events once, then 404, then shows, then 404, then shows.
I turned on error reporting in the wp-config file and saw this error on the site:
Notice: Undefined property: WP_Query::$tribe_is_event_query in /home2/mysite/public_html/wp-content/plugins/the-events-calendar/lib/the-events-calendar.class.php on line 2127
I don't know if that is related to the 404 error being generated randomly or not.
I tried doing a clean install of The Events Calendar plugin on another site, and the View All Events link goes to:
/events/month/ rather than /events/upcoming/
I did a clean install of The Events Calendar plugin on the bcap.org site, but this did not change the problem.
The problems started occurring after the major update to The Events Calendar.