How to parse an escaped json string with ansible/jmespath/jq?

I'm using the Ansible module for Bluecat to make an authorized API call to get some information about a subnet. The response looks something like this:

"result": {
        "changed": false,
        "failed": false,
        "json": "b'{\"id\":12345,\"name\":\"SUBNET NAME\",\"properties\":\"CIDR=10.2.2.0/24|allowDuplicateHost=enable|pingBeforeAssign=disable|inheritAllowDuplicateHost=true|inheritPingBeforeAssign=true|gateway=10.2.2.1|inheritDNSRestrictions=true|inheritDefaultDomains=true|inheritDefaultView=true|\",\"type\":\"IP4Network\"}\\n'",
        "msg": "",
        "status": 200
}

As you can see, all the useful data is in that json field, but it's some string literal abomination with escaped quotes and newlines. If I run

- debug:
      msg: "{{ result | json_query('json.name') }}"

in Ansible, it gives me back the msg field instead! I can get the entire json field, but not anything inside it. If I tinker with it a little bit and trim the b at the beginning, the inner single quotes, and the extra backslash by the newline at the end, then jq .json | fromjson parses it correctly. But I'm fairly certain b'' just means byte encoding and shouldn't break the parsing, but it does. And what's with the double backslashes at the end? Do I have any options beyond using some sed black magic to wipe out all of the escape characters? Why would a web API return a string literal like this?