If you’re using get_posts on your listing, please use WP_Query instead.

On page templates, add the “facetwp” WP_Query argument like so:

<?php
$args = [
    'post_type' => 'event',
    'posts_per_page' => 10,
    'facetwp' => true, // we added this
];
$query = new WP_Query( $args );

This tells FacetWP that it’s the correct query to use for filtering.