railsで422 (Unprocessable Entity)の原因が分からない

お世話になっております。

前提・実現したいこと

devise、devise_token_authを使用してrailsAPIでのユーザー登録機能を実装しているのですが、
バリデーションに引っかかるデータや、空のデータを送ると422 (Unprocessable Entity)がログに表示されます。
この原因が分かりません。

発生している問題・エラーメッセージ

######curlした際のレスポンス

~ ❯❯❯ curl localhost:3001/api/auth -X POST -d '{"name":"", "email":"example@example.com", "password":"password", "password_confirmation": "passwor"}' -H "content-type:application/json"
{"status":"error","data":{"id":null,"provider":"email","uid":"","name":"","image":null,"email":"example@example.com","allow_password_change":false,"created_at":null,"updated_at":null},
"errors":{"password_confirmation":["doesn't match Password"],"email":["has already been taken"],"name":["can't be blank"],"full_messages":["Password confirmation doesn't match Password","Email has already been taken","Name can't be blank"]}}%

######railsのログ

Started POST "/api/auth/" for 172.23.0.1 at 2020-05-14 13:16:28 +0900
Processing by Api::Auth::RegistrationsController#create as HTML
  Parameters: {"name"=>"", "email"=>"", "password"=>"[FILTERED]", "password_confirmation"=>"[FILTERED]"}
   (1.1ms)  BEGIN
  User Exists? (1.7ms)  SELECT 1 AS one FROM `users` WHERE `users`.`email` = BINARY '' AND `users`.`provider` = 'email' LIMIT 1
  User Exists? (1.6ms)  SELECT 1 AS one FROM `users` WHERE `users`.`email` = '' LIMIT 1
   (3.3ms)  ROLLBACK
Completed 422 Unprocessable Entity in 68ms (Views: 0.7ms | ActiveRecord: 7.6ms | Allocations: 7500)

該当のソースコード

以下はブラウザの検証機能のnetworkにあった、422errorの内容です。
######General

Request URL: http://localhost:3000/api/auth/
Request Method: POST
Status Code: 422 Unprocessable Entity
Remote Address: 127.0.0.1:3000
Referrer Policy: no-referrer-when-downgrade

######Request Headers

Accept: application/json, text/plain, */*
Accept-Encoding: gzip, deflate, br
Accept-Language: ja,en-US;q=0.9,en;q=0.8
Connection: keep-alive
Content-Length: 63
Content-Type: application/json;charset=UTF-8
Cookie: _ranking_app_session=lzmtqj9bPHkOBVy%2BACi3aADojSsDzd%2BnXOlYmM1KHJK7MAlH8gCWJWMh0ohOJHejWR4UqoCsyprlkboW4kJjWsulpwxfKg5pDMuZfeEOEG8lQ84LYUnWiFf5ORUT7uuUb0iRI7NIYr%2FffAd4%2BAc%3D--fP5VYg83rpGQ2SVI--vp2NeUd%2F56ei1pTrs5Di%2FA%3D%3D
Host: localhost:3000
Origin: http://localhost:3000
Referer: http://localhost:3000/signup
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.129 Safari/537.36

######Response Headers

access-control-allow-methods: GET, POST, PUT, PATCH, DELETE, OPTIONS, HEAD
access-control-allow-origin: *
access-control-expose-headers: 
access-control-max-age: 7200
cache-control: no-cache
connection: close
content-type: application/json; charset=utf-8
Date: Thu, 14 May 2020 04:23:16 GMT
referrer-policy: strict-origin-when-cross-origin
transfer-encoding: chunked
vary: Origin
x-content-type-options: nosniff
x-download-options: noopen
x-frame-options: SAMEORIGIN
x-permitted-cross-domain-policies: none
x-request-id: 1aa46f75-881f-423f-acb5-280eac741eff
x-runtime: 0.114484
x-xss-protection: 1; mode=block

######Request Payload

{name: "", email: "", password: "", password_confirmation: ""}
email: ""
name: ""
password: ""
password_confirmation: ""

以下はrailsの情報です。
######controllers/api/auth/registrations_controller.rb

ruby
1class Api::Auth::RegistrationsController < DeviseTokenAuth::RegistrationsController
2  private
3
4  def sign_up_params
5    params.permit(:name, :email, :password, :password_confirmation)
6  end
7
8  def account_update_params
9    params.permit(:name, :email)
10  end
11end

######controllers/application_controller.rb

ruby
1class ApplicationController < ActionController::Base
2  include DeviseTokenAuth::Concerns::SetUserByToken
3  skip_before_action :verify_authenticity_token, if: :devise_controller?
4end
5