Thought I would share in case anyone else was having a similar problem, as this may solve some pretty big headaches.
If you are using Easy Content Types from Pippin’s Plugins
http://pippinsplugins.com/easy-content-types/
Make sure to you go into your WP-Admin Content Types -> Settings
and make sure the box is CHECKED for “Disable Taxonomy Archives Fix”
Keep reading for technical info:
In the Easy Contents Plugin register-taxonomies.php there is a function that is great if you are using a vanilla install and not doing much customization.
add_filter( ‘pre_get_posts’, ‘ecpt_on_pre_get_posts’, 999 );
This filter will always run AFTER the pre_get_posts filters create by tribe_events class, so it changes your WP_QUERY post_type arg, to the array of your custom post types instead of TribeEvents::POSTTYPE
which will always return a negative result.
The only other way around that, is if the Tribe developers decided to add a $query->query_vars[‘suppress_filters’] to the pre_get_posts function in tribe-event-query.class.php – in which case would ignore all other plugin query filters (assuming the plugins are coded correctly)