"move" operation and gateways

It doesn't detect gateways because you are using M_active_gateways and not membership_activated_gateways.
We can see in class.gateways.php two functions that do the same thing :
toggleactivation and activate. (I think toggleactivation is an old function.)

And in function handle_member_gateway_op :

Error 1 :
// $active = get_option('M_active_gateways', array());
$active = get_option('membership_activated_gateways', array());

Error 2 and 3 (twice) :
// if(array_key_exists($key, $active)) {
if(in_array($key, $active)) {

After that, move operation works.