FacetWP - automatically support taxonomy terms containing numbers

functions.php

<?php

// Add the following to your (child) theme's functions.php and re-index afterwards

add_filter( 'facetwp_index_row', function( $params, $class ) {
    $term_id = (int) $params['term_id'];
    $display_value = $params['facet_display_value'];

    // If this is a taxonomy term and the display value is numeric,
    // Then set facet_value = facet_display_value
    if ( 0 < $term_id && is_numeric( $display_value ) ) {
        $params['facet_value'] = $display_value;
    }

    return $params;
}, 10, 2 );