In includes/modules/payment/authorizenet_cim.php, the function getCustomerCards() returns the query result. Did you intend the process the query result and return an array as was done in includes/modules/payment/authorizenet_cof.php ? Because the way it is now makes no sense - see the references to the results of getCustomerCards in admin/includes/classes/observers/class.cim_admin_observer.php line 65 and 72 for example

$key = array_search($cc_index, array_column($cards, 'id'));