<?php
// ACF json autosave
add_filter('acf/settings/save_json', 'my_acf_json_save_point');
function my_acf_json_save_point( $path ) {
    $path = BW_PATH. 'backup/acf';
    return $path;
}

// ACF json load
add_filter('acf/settings/load_json', 'my_acf_json_load_point');
function my_acf_json_load_point( $paths ) {
    unset($paths[0]);
    $paths[] = BW_PATH. 'backup/acf';
    return $paths;
}