Intermittent 400 response with empty body

Hi,

We have been seeing random 400 responses with empty bodies from Pipedrive lately on the API https://api.pipedrive.com/v1/persons.
It occurs intermittently with different start and limit params, while retrying the same failed request would yield successful response.

Example 400 response:

{
  "version": "1.1",
  "body": "",
  "uri": {
    "scheme": "https",
    "user": null,
    "password": null,
    "host": "api.pipedrive.com",
    "port": null,
    "path": "/v1/persons",
    "query": "start=0&limit=500&api_token=token",
    "fragment": null
  },
  "status": 400,
  "headers": [
    [
      [
        "Date",
        "Mon, 29 Oct 2018 04:54:34 GMT"
      ],
      [
        "Transfer-Encoding",
        "chunked"
      ],
      [
        "Connection",
        "close"
      ],
      [
        "X-Correlation-Id",
        "xxx"
      ],
      [
        "Badi",
        "Routing: us-east-1=>chi; Version: 4fcb;"
      ],
      [
        "Access-Control-Expose-Headers",
        "X-RateLimit-Remaining, X-RateLimit-Limit, X-RateLimit-Reset"
      ],
      [
        "X-Newrelic-App-Data",
        "xxx"
      ],
      [
        "Set-Cookie",
        "pipe-last-active=xxx;path=/;domain=.pipedrive.com;expires=0"
      ],
      [
        "X-Ratelimit-Limit",
        "200"
      ],
      [
        "X-Ratelimit-Remaining",
        "199"
      ],
      [
        "X-Ratelimit-Reset",
        "10"
      ],
      [
        "Server",
        "no-name-at-all"
      ],
      [
        "X-Xss-Protection",
        "1; mode=block"
      ],
      [
        "X-Content-Type-Options",
        "nosniff"
      ],
      [
        "Strict-Transport-Security",
        "max-age=31536000; includeSubDomains"
      ]
    ]
  ]
}

Do you know when this started for you?