vCloud HTTPS monitor broke after upgrade of backend vCloud director

I have a very simple monitor for vCloud director.

the Send String was

GET /cloud/server_status \r\n

and the receive String was

Service is up.

This was happy and fine, then we upgraded from vCloud 9.0 to 9.5 and suddenly the monitor started failing. We still have both versions running so I can do comparisons. Initially the monitor error stated that HTTP 0.9 wasn't supported on the backend server, so I modified the Send String to send that included HTTP 1.1 thinking this would sort me out.

So now my Send String looks like

GET /cloud/server_status HTTP/1.1\r\n\r\n

and Receive String looks like

Service is up. HTTP/1.1

The F5 monitor is saying its getting back a 400 bad request error but I'm really unsure why.

Doing a verbose curl I get the following response.

Legacy 9.0
< HTTP/1.1 200 OK
< Date: Mon, 25 Feb 2019 19:37:47 GMT
< X-VMWARE-VCLOUD-REQUEST-ID: 46386830-291d-45ab-89ce-c89188dc2746
< Cache-Control: no-cache, no-store, max-age=0, must-revalidate
< Pragma: no-cache
< Expires: 0
< Strict-Transport-Security: max-age=31536000 ; includeSubDomains
< X-XSS-Protection: 1; mode=block
< X-Frame-Options: SAMEORIGIN
< X-Content-Type-Options: nosniff
< Transfer-Encoding: chunked
<
Service is up.* Connection 0 to host host.name left intact

Updated 9.5 Response

HTTP/1.1 200 OK
< Date: Mon, 25 Feb 2019 19:37:02 GMT
< X-VMWARE-VCLOUD-REQUEST-ID: b1e654da-ef3d-4560-aad3-6690509ce219
< Strict-Transport-Security: max-age=31536000 ; includeSubDomains
< X-XSS-Protection: 1; mode=block
< X-Frame-Options: SAMEORIGIN
< X-Content-Type-Options: nosniff
< Content-Security-Policy: default-src *  data: blob: 'unsafe-inline' 'unsafe-eval'; script-src * 'unsafe-inline' 'unsafe-eval'; connect-src * 'unsafe-inline'; img-src * data: blob: 'unsafe-inline'; frame-src *; style-src * data: blob: 'unsafe-inline'; font-src * data: blob: 'unsafe-inline';
< Vary: Accept-Encoding, User-Agent
< Transfer-Encoding: chunked
<
Service is up.* Connection 0 to host host.name left intact

So I'm really confused as to what it is about the new response thats breaking the monitor. Any suggestions are appreciated.