Did you try to load the json manually with the acf/settings/load_json
filter?
// Load ACF JSON for sync
add_filter( 'acf/settings/load_json', function( $paths ) use ( $acf_path ) {
// remove original path (optional)
unset( $paths[0] );
// append path
$paths[] = $acf_path;
// return
return $paths;
} );