the logic here https://phabricator.wikimedia.org/diffusion/WFCG/browse/master/ext/wmf-civicrm/Civi/Api4/Action/WMFContact/Save.php$748
causing us create more new contacts if donor have more than one contacts exists.
Let's update logic to returning oldest cid instead of null.
agreed during tech talk with Elliott Eileen Lars and Christine