Post Types Order breaks ajax requests in The Events Calendar

If I disable admin sort, the calendar is working properly again.

This issue impacted me too, but with the FacetWP plugin. It looks like every plugin that uses an AJAX request to list content would be impacted.

Here’s the support page from FacetWP on the issue:
https://facetwp.com/compatibility-with-the-post-types-order-plugin/

FYI, WordPress considers AJAX requests to occur within the admin scope, even if they are made by unauthenticated visitors. The AJAX URL used by every plugin and theme is /wp-admin/admin-ajax.php.

What I find particularly horrible about this conflict, is that it impacts post types that aren’t even managed using the Post Types Order plugin.

Since pluginv ersion 1.8.7, You can use a filter pto/posts_orderby to force any sort to apply on certain queries, an example usage for this filter can be found at https://www.nsp-code.com/ignore-sort-apply-for-certain-query-on-post-types-order/