Cannot return null for non-nullable field RenamedTitleEvent.currentTitle (web page down - code 500)

Hi, I’m doing some queries and found the following error:

Cannot return null for non-nullable field RenamedTitleEvent.currentTitle

for the following query:

query {
  node(id: "MDU6SXNzdWUzNjM1MDE1MzI=") {
    __typename
    ... on Issue {
      title
      number
      timeline (first: 100) {
        totalCount
        nodes {
          __typename
          ... on RenamedTitleEvent {
            previousTitle
            currentTitle
          }
        }
      }
    }
  }
}

and get the following response:

{
  "data": {
    "node": {
      "__typename": "Issue",
      "title": "[Bug Report] official website documents are not good enough to improve.\n",
      "number": 4578,
      "timeline": {
        "totalCount": 2,
        "nodes": [
          [
            [
              "__typename",
              "IssueComment"
            ]
          ],
          null
        ]
      }
    }
  },
  "errors": [
    {
      "message": "Cannot return null for non-nullable field RenamedTitleEvent.previousTitle"
    }
  ]
}

I also noticed that the website page is also down.

https://github.com/iview/iview/issues/4578

If you haven’t already, please contact us at git.io/c with the info so we can look into that further.