problem resolved.
Issue:
My WP is a multi-site installation that is also load-balanced behind a firewall. This causes all APIs related to WP_Http get to be processed differently.
Resolution:
I modified line 167 to hardcode the actual server.
from
$url = get_bloginfo(‘url’) . ‘/’ . $wp->request . “?$query_string”;
to:
$url = “https://<my_server_address>” . ‘/’ . $wp->request . “?$query_string”;