<?php

function fwp_ignore_query( $is_main_query, $query ) {
    if ( isset( $query->query_vars['posts_per_page'] ) && 30 == (int) $query->query_vars['posts_per_page'] ) {
        $is_main_query = false;
    }
    return $is_main_query;
}
add_filter( 'facetwp_is_main_query', 'fwp_ignore_query', 10, 2 );