Custom Post type is being ignored in query

I found out that I was using pre_get_post on these pages to exclude some things on the taxonomy archive pages.

add_action( 'pre_get_posts', 'exclude_cpt' );
function exclude_cpt( $query ) {
    if ( $query->is_tax('results_categories') ) {
         $query->set( 'post_type', array('results') );
    }
    return $query;
}

BUT I forgot to make sure this was only happening in the main query, the final function is below.

add_action( 'pre_get_posts', 'exclude_cpt' );
function exclude_cpt( $query ) {
    if ( $query->is_tax('results_categories') && $query->is_main_query() ) {
         $query->set( 'post_type', array('results') );
    }
    return $query;
}