[BUG]: [Create Review] 422: Unprocessable Entity: Review comments is invalid and Review threads is invalid

Start with the Create a review API documentation linked in the issue and compare the first and second request payloads in the provided log. Reproduce the batched requests using actions/github-script v6, then determine whether the failure is caused by a documented comments limit, request validation, rate limiting, or spam protection.

What happened?

Use Case,

I'm using Create review PR API to create PR comments by sending multiple comments as array in single request input field comments. It works as expected.

Issue,

When I tried to split single request Create review PR API into multiple requests by limiting comments input batch array of 20 comments per API call then it succeeds for first batch but second batch request fails with error "422: Unprocessable Entity: Review comments is invalid and Review threads is invalid"

Failed response status,

422 Validation failed, or the endpoint has been spammed.

Limitation?

Do we have any maximum number/length/character limitation for comments array in single request Create review PR API input field comments

Root Cause?

Why issue happens only for multiple requests to Create review PR API? Is that due to rate limiting/spam issues for endpoint?

Versions

actions/github-script@v6, octokit-core.js/3.6.0, Node.js/16.13.0 (linux; x64)

Relevant log output

RequestError [HttpError]: Unprocessable Entity: "Review comments is invalid and Review threads is invalid"
    at /runner/_work/_actions/actions/github-script/v6/dist/index.js:6172:21
    at processTicksAndRejections (node:internal/process/task_queues:96:5) {
  status: 422,
  response: {
    url: 'https://api.github.com/repos/{ORG}/{REPO}/pulls/{PR}/reviews',
    status: 422,
    headers: {
      'access-control-allow-origin': '*',
      'access-control-expose-headers': 'ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Used, X-RateLimit-Resource, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type, X-GitHub-SSO, X-GitHub-Request-Id, Deprecation, Sunset',
      connection: 'close',
Error: Unhandled error: HttpError: Unprocessable Entity: "Review comments is invalid and Review threads is invalid"
      'content-length': '206',
      'content-security-policy': "default-src 'none'",
      'content-type': 'application/json; charset=utf-8',
      date: 'Wed, 21 Dec 2022 07:14:45 GMT',
      'referrer-policy': 'origin-when-cross-origin, strict-origin-when-cross-origin',
      server: 'GitHub.com',
      'strict-transport-security': 'max-age=31536000; includeSubdomains; preload',
      vary: 'Accept-Encoding, Accept, X-Requested-With',
      'x-accepted-oauth-scopes': '',
      'x-content-type-options': 'nosniff',
      'x-frame-options': 'deny',
      'x-github-api-version-selected': '2022-11-28',
      'x-github-media-type': 'github.v3',
      'x-github-request-id': 'FDAD:1CB0:FEC18:12B194:63A2B260',
      'x-oauth-scopes': 'repo',
      'x-ratelimit-limit': '5000',
      'x-ratelimit-remaining': '4819',
      'x-ratelimit-reset': '1671608480',
      'x-ratelimit-resource': 'core',
      'x-ratelimit-used': '181',
      'x-xss-protection': '0'
    },
    data: {
      message: 'Unprocessable Entity',
      errors: [Array],
      documentation_url: 'https://docs.github.com/rest/reference/pulls#create-a-review-for-a-pull-request'
    }
  },
  request: {
    method: 'POST',
    url: 'https://api.github.com/repos/{ORG}/{REPO}/pulls/{PR}/reviews',
    headers: {
      accept: 'application/vnd.github.-preview+json',
      'user-agent': 'actions/github-script octokit-core.js/3.6.0 Node.js/16.13.0 (linux; x64)',
      authorization: 'token [REDACTED]',
      'content-type': 'application/json; charset=utf-8'
    },
    body: '{"event":"COMMENT","commit_id":"a6f6058f93f6bc119324e4824248d6206d087b86","comments":[{COMMENTS_ARR}]}',
    request: { agent: [Agent], hook: [Function: bound bound register] }
  }
}