Issues with Chef 12 server and a bootstrap proxy

I have a squid proxy server for a lab that doesn't generally have internet connectivity. What I've found is that I can't make that work with chef 12 with the proxy, but can without the proxy, and with a chef 11 server both settings work. I tried to debug the 404 with just curl, but both chef 11 and chef 12 I get 404's when connecting through a proxy but at least interesting html when I drop the proxy
, i.e.

$  curl --proxy http://10.0.0.201:3128 -k https://ip-10-0-0-178/organizations/girdev
curl: (56) Received HTTP code 404 from proxy after CONNECT

curl --proxy http://10.0.0.201:3128 -k https://ip-10-0-0-184
curl: (56) Received HTTP code 404 from proxy after CONNECT

$ knife bootstrap --bootstrap-proxy 'http://10.0.0.201:3128' --node-name 'gir-dev-repo-02' 10.0.0.224
Doing old-style registration with the validation key at /Users/josh/workspace/projects/chefgen/gir/aws/.chef/chef-validator.pem...
Delete your validation key in order to use your user credentials instead

Connecting to 10.0.0.224
10.0.0.224 Starting first Chef Client run...
10.0.0.224 Starting Chef Client, version 12.3.0
10.0.0.224 Creating a new client identity for gir-dev-repo-02 using the validator key.
10.0.0.224
10.0.0.224 ================================================================================
10.0.0.224 Chef encountered an error attempting to create the client "gir-dev-repo-02"
10.0.0.224 ================================================================================
10.0.0.224
10.0.0.224 Resource Not Found:
10.0.0.224 -------------------
10.0.0.224 The server returned a HTTP 404. This usually indicates that your chef_server_url is incorrect.
10.0.0.224
10.0.0.224 Relevant Config Settings:
10.0.0.224 -------------------------
10.0.0.224 chef_server_url "https://ip-10-0-0-178/organizations/girdev"
10.0.0.224

With a chef 11 server the previous command works as expected, as it does with chef 12 if I don't have a bootstrap proxy

Start at the knife bootstrap entry point and reproduce the shown Chef 12 bootstrap-proxy command, comparing it with Chef 11 and with the proxy disabled. Investigate the differing HTTP 404 behavior from the supplied curl and bootstrap output; done means Chef 12 can bootstrap through the Squid proxy without the 404.