I noticed something, I am not 100% sure of it, but it happens only on pages going through IIRF.
IIRF (the latest version at least) seems to "duplicate" the response code in the message, for example
"HTTP/1.1 200 OK"
"HTTP/1.1 200 200 OK"
This seems to happen on all the response messages.
Can someone please confirm the issue before I open an issue?