Hi @lenar ,
You could hook into the acf/load_value as in the example below.
add_filter('acf/load_value/type=repeater', 'my_acf_load_value', 10, 3);
function my_acf_load_value( $rows)
{
array_multisort($rows, SORT_ASC);
return $rows;
}
Hope this helps.