400 Error trying to create document

[cmbirk]

I'm getting this response from the POST to /api/docs

{
  "error": "E_VALIDATION",
  "status": 400,
  "summary": "1 attribute is invalid",
  "model": "Document",
  "invalidAttributes": {
    "publish_state": [
      {
        "rule": "string",
        "message": "`undefined` should be a string (instead of \"null\", which is a object)"
      },
      {
        "rule": "required",
        "message": "\"required\" validation rule failed for input: null"
      }
    ]
  }
}

and it looks like this was the request payload:

{title: "documents.list.new.blank"}

but the rest of the page is rendering the locales correctly.