CyberSource order gets stuck 'In Checkout', never completes
Figured out the issue: In uc_cybersource.module there is a line in function uc_cybersource_hop_form($form_state, $order) that reads

$data['orderPage_version'] = '4';


It needs to be changed to the current orderPage version (as of this writing it is 7).

$data['orderPage_version'] = '7';


This should definitely be documented somewhere!