frontend submit post jQuery clone row won’t save

Double check if your <div id='repeater'> is properly inside <form> tag of your page ( I assume you’re in a form since your code does not provide an ajax function) and from what you outpup with var_dump($_POST['al_ttl']) it may be the reason of Undefined index: al_ttl.

Also note that you’re overwriting the first initialization of $post_id with wp_insert_post and after that you’re looking for a post_meta $old = get_post_meta($post_id, 'data_rows', true); which will always be empty being on the new post