$changes array is empty

I’m trying to write a hook but the $changes array appears to be empty. Is it my code or is there a problem with the hook? The $user_id is present but nothing for $changes.

add_action( ‘um_after_user_account_updated’, ‘ikorcc_after_user_account_updated’, 10, 2);

function ikorcc_after_user_account_updated( $user_id, $changes ){
ob_start();

echo "User ID: " . $user_id . "\nChanges:\n";
foreach($changes as $key => $data) {
    echo $key . ': ' . (is_array($data) ? print_r($data, true) : $data) . "\n";
}

$contents = ob_get_contents();
ob_end_clean();

$admin_email = UM()->options()->get( 'admin_email' );
wp_mail( $admin_email,'User Account Updated', $contents );

}